Design Brief: A Tower Defense (part 3)
Last part, I promise.
So first part was the Towers, second part the Creeps, this part will be the player cast spells and potential issues with the game.
Onward we go!
Spells
Now what do I mean by spells?
The thing is, Tower Defense games can be very boring. Especially ones like ours where you're not crafting the maze, only placing the towers. It's quite common that you place the towers, then Ctrl+Tab to another tab and surf the net for that wave. We want people to take part in the battle and not set it up then let the game play itself.
That is why I propose the use of spells, abilities the player can activate at any time that have an effect on the battlefield. This gives the player more control over what is happening on the field and lets them counter any weaknesses in their towers.
I beleive this is important because Tower Defenders are one of the few games left that take after the Arcades, once you die in a TD you start over from the beginning, so if you make a few mistakes in your towers you lose. I don't like punishing the player as harshly as this, which is why I propose the inclusion of such spells to let a player who built things poorly to still stand a chance. Of course this means the normal mode will get stomped over by experienced TD players, this is why we include other game modes like "No spells" or "Hard mode" but more on that later. Let's look at some spells.
Mana
On the towers section I mentioned mana. Mana is your spellcasting resource, the more of it you have the more spells you can cast. It restores automatically on its own but this can be increased through the water tower, which grants you mana on every shot the tower takes.
Lets set a max mana value of 100. Mana restoration rate will require a lot of playtesting, but for an initial value lets go at 3 mana for every 5 seconds. Which is 100 mana after 2 minutes and 50 seconds.
Fireball
When you select a tower and hover over tiles ready to place it, you get a circle around your pointer which shows the range of that tower. Fireball works in a similar way. When you select it your pointer will have a ring around showing the range of the spell. Clicking anywhere on the screen will have you drop a fireball at that location dealing damage to everything in its radius.
This damage needs to be significant but not boss-one-shot. So I'd propose the damage is a % of the creeps health depending on whether the creep is a boss or a regular creep.
e.g. Creep - 60% of max health. Boss - 30% of max health. This spell bypasses magic immunity, shields and damage reduction.
Due to its obvious power over bosses we must prevent it being able to be cast multiple times in a row very quickly. So it should have a mana cost of greater than 50, I propose 55. So at full mana using this spell once drops you to 45 mana. With natural regeneration it will take 20 seconds to be able to cast the spell again. Plenty of time for your towers to take out the boss, but not long enough for the boss to escape, letting you drop another Fireball on him if necessary.
Freeze
Ice Towers slow down creeps, but in a small area. Freeze will slow down everything on the map to the same amount as Ice Block, the single target Ice Tower. This effect will only last a few seconds. Mana cost? I'm guessing about 40. That'll let you use it twice in quick succession or combo a Freeze with a Fireball if needed.
Confusion (As suggested)
The creeps become confused and disoriented and they walk backwards for 5 seconds. After 5 seconds they realise they've been duped and become enraged and move 25% faster and are immune to new Confusion effects.
This is a high-risk, high-reward card. It's great if you only have a couple of creeps left and need those last few seconds to take them out but it's poor on lots of creeps and even poorer on Sprinters.
I believe even if we set the mana cost to 20, players will rarely use this card except for the last couple of creeps per wave and abuse it on bosses. Confusion followed by a Freeze would be a lethal combination as that's effectively 10 seconds of controlling the mob, 15 if you use Freeze a second time. Even with a poor tower build, 15 seconds is a near guaranteed kill.
We could remove the move speed increase part of enrage, letting the spell be more widely used, and then allow the enrage to prevent slowing through freeze as well as preventing confusion. This however has the problem of a player going Freeze-Freeze-Confusion instead of Confusion-Freeze-Freeze.
So lets make the mana cost 40 and remove the negative effect, but prevent Confusion from being cast twice in succession by the Enrage immunity. This in total will let the player freeze-confuse mobs for 10 seconds total.
Poison
Poison will poison everything on the map, dealing 5% of their total health in damage every second for 10 seconds. Bosses are immune.
Bosses are supposed to be reasonably challenging, dropping a Poison on their heads cuts their health in half. So either we make their health so high that Poisoning them is a necessity to fight them or Poison will be horribly overpowered against all bosses.
If Poison can hit a boss, it becomes the only way to play. So we make them immune. Due to the immense total damage Poison can spit out, it'll have to cost at least 75 mana. Yes Fireball does more damage, but only in a small area, Poison hits everything on the map.
I'm almost certain that 5% health is too much damage and would need to be dropped to about 3%, for 30% total. But this would come out in testing.
Frenzy
Gives your towers a boost of speed, letting all of them hit 30% faster for 10 seconds. Costs 60 mana.
Straight and to the point, this one doesn't affect the enemies, it affects your towers.
Preserve Life
100 mana, lose no lives this wave. This is a Panic Button spell, if everything is going bad and your towers are failing. This is an option to keep yourself afloat just a little longer. It also gives the player an interesting choice "Do I use my spells to kill these creeps? Or absorb the damage?" In practice I'd imagine this spell would provide little help, as even if you survive this wave, if your tower damage is THAT low that you needed to blow Preserve Life then you're not surviving the next wave. Most likely this becomes the de factor spell of the last boss.
Potential Issues
This design has a lot of potential issues. Some I've addressed, some I haven't. I'm going to look at a bunch of them and expand upon them, and brainstorm solutions.
Overpowered Spells
The reason spells are added is to give the player something to do during waves. To alleviate the tedium that comes with Tower Defense games and how non-interactive their combat is. But the mechanics I listed above have potential to be too powerful and make them game uninteresting. Obviously a lot of testing will need to be done to verify this, but I still strongly suspect them to be more powerful than intended.
One of these problems is actually the Mana. If the player builds quite a few water towers the mana bonus they'd give would negate the high cost of some of these cards allowing them to be used very frequently. We can offset this by vastly reducing the damage water towers too so they are horribly outclassed at later levels forcing the player to use spells more frequently. This is quite a valid strategy and something I'd like to see in action, but what I'm concerned about is players who build 2 or 3 water towers at most and the rest normal magic/physical towers. Then they're getting the benefit of high mana regeneration without losing much damage.
An option is to remove mana and instead give every spell a cooldown relative to how long it would have taken to restore the mana. Fireball was 55 mana, which at 3 mana every 5 seconds is 95 seconds. So if most of the spells had a cooldown of about 100 seconds, but could all be used at once, you'd absolutely slaughter the wave you're on. But it'll be 100 seconds before anything is ready again. The Water Tower would need to be redesigned to do damage and maybe inflict critical hits, or every shot against a creep does increasingly more damage (Chinese water torture tower \m/ ).
Calling waves
Calling in extra waves seems to be a standard in Tower Defense games, and a good thing it is too. I played some of the earlier ones and it sucked waiting 10-15 seconds for the next wave to hurry up and get there. The question is do we allow players to call in as many waves as they want? Or just one at a time?
Score, Maps and other options
Why play? Why play more than once? What purpose is there for going through it all again?
Desktop Defender on Facebook has competitive scores and difficulties. By killing creeps you get points, by killing them quickly you get more points. By keeping your lives you have even more points. Each difficulty has a multiplier associated with it. So higher difficulties are a bigger multiplier and a higher score. With score we could allow other spells, such as increasing the speed of creeps but granting a higher score for each kill. A good risk-reward scenario.
This could be something to appeal to the more hardcore audience, by allowing multiple difficulties and scaling creep health and number of waves based on difficulty you can give them something to aim for. A High Score. This kind of gameplay also forces effective tower and spell use, the casual player can play on any difficulty and enjoy the game. The hardcore player gets to try and find the best combination of towers and spells to beat all the waves.
Multiple maps is another option. Even if score is not the issue, varying maps will change the difficulty and force different tactics. Bubble Tanks Tower Defense has a map select screen and every map has three shades of colour. Dark means you've never beat the map. Lit up means you've completed the map. Lit up with a white aura means you didn't lose a single life when you beat the map.
The desire to have every map with a white aura is a compelling motivator for replay. It's also possible that some of these maps will be mazing maps, where there is no fixed maze and the player must build towers to form a maze to force the creeps through. It adds a different dimension to the game and some towers which are great on a fixed map, might not be in a maze map.
In addition to this are various game modes.
100 waves - If we have 50 waves as standard, let this one have 100. Double the waves means double the game length and the health of wave 100 will be enormous.
No spells - You only have your towers, no spells.
Fixed cash - You start with 10'000G. You get no gold no for killing creeps, set up your defenses and let the good times roll.
Fixed number of towers - You can only place 10 towers. Choose wisely.
Fixed positions - Only 10 squares on the map can have towers placed on them. Which towers will you pick? Similar to fixed number, but this one restricts position as well as limiting number.
Infinite Waves - They just... keep... coming. How long will you survive?
Night of the Dead - After killing a creep, a couple of seconds later... it gets back up as a Zombie! With full health! But half movement speed... so it's not that bad, except that even as undead they keep all their special abilities. Oh dear lord... Sloth Boss Zombie.
The End
I gotta say. I want to play this game now. Zombie Mode sounds quite fun and it would be interesting to see what sorta of tower setups you'd need to do to take on both the living and dead versions of each wave.
Now... what should I design next...
So first part was the Towers, second part the Creeps, this part will be the player cast spells and potential issues with the game.
Onward we go!
Spells
Now what do I mean by spells?
The thing is, Tower Defense games can be very boring. Especially ones like ours where you're not crafting the maze, only placing the towers. It's quite common that you place the towers, then Ctrl+Tab to another tab and surf the net for that wave. We want people to take part in the battle and not set it up then let the game play itself.
That is why I propose the use of spells, abilities the player can activate at any time that have an effect on the battlefield. This gives the player more control over what is happening on the field and lets them counter any weaknesses in their towers.
I beleive this is important because Tower Defenders are one of the few games left that take after the Arcades, once you die in a TD you start over from the beginning, so if you make a few mistakes in your towers you lose. I don't like punishing the player as harshly as this, which is why I propose the inclusion of such spells to let a player who built things poorly to still stand a chance. Of course this means the normal mode will get stomped over by experienced TD players, this is why we include other game modes like "No spells" or "Hard mode" but more on that later. Let's look at some spells.
Mana
On the towers section I mentioned mana. Mana is your spellcasting resource, the more of it you have the more spells you can cast. It restores automatically on its own but this can be increased through the water tower, which grants you mana on every shot the tower takes.
Lets set a max mana value of 100. Mana restoration rate will require a lot of playtesting, but for an initial value lets go at 3 mana for every 5 seconds. Which is 100 mana after 2 minutes and 50 seconds.
Fireball
When you select a tower and hover over tiles ready to place it, you get a circle around your pointer which shows the range of that tower. Fireball works in a similar way. When you select it your pointer will have a ring around showing the range of the spell. Clicking anywhere on the screen will have you drop a fireball at that location dealing damage to everything in its radius.
This damage needs to be significant but not boss-one-shot. So I'd propose the damage is a % of the creeps health depending on whether the creep is a boss or a regular creep.
e.g. Creep - 60% of max health. Boss - 30% of max health. This spell bypasses magic immunity, shields and damage reduction.
Due to its obvious power over bosses we must prevent it being able to be cast multiple times in a row very quickly. So it should have a mana cost of greater than 50, I propose 55. So at full mana using this spell once drops you to 45 mana. With natural regeneration it will take 20 seconds to be able to cast the spell again. Plenty of time for your towers to take out the boss, but not long enough for the boss to escape, letting you drop another Fireball on him if necessary.
Freeze
Ice Towers slow down creeps, but in a small area. Freeze will slow down everything on the map to the same amount as Ice Block, the single target Ice Tower. This effect will only last a few seconds. Mana cost? I'm guessing about 40. That'll let you use it twice in quick succession or combo a Freeze with a Fireball if needed.
Confusion (As suggested)
The creeps become confused and disoriented and they walk backwards for 5 seconds. After 5 seconds they realise they've been duped and become enraged and move 25% faster and are immune to new Confusion effects.
This is a high-risk, high-reward card. It's great if you only have a couple of creeps left and need those last few seconds to take them out but it's poor on lots of creeps and even poorer on Sprinters.
I believe even if we set the mana cost to 20, players will rarely use this card except for the last couple of creeps per wave and abuse it on bosses. Confusion followed by a Freeze would be a lethal combination as that's effectively 10 seconds of controlling the mob, 15 if you use Freeze a second time. Even with a poor tower build, 15 seconds is a near guaranteed kill.
We could remove the move speed increase part of enrage, letting the spell be more widely used, and then allow the enrage to prevent slowing through freeze as well as preventing confusion. This however has the problem of a player going Freeze-Freeze-Confusion instead of Confusion-Freeze-Freeze.
So lets make the mana cost 40 and remove the negative effect, but prevent Confusion from being cast twice in succession by the Enrage immunity. This in total will let the player freeze-confuse mobs for 10 seconds total.
Poison
Poison will poison everything on the map, dealing 5% of their total health in damage every second for 10 seconds. Bosses are immune.
Bosses are supposed to be reasonably challenging, dropping a Poison on their heads cuts their health in half. So either we make their health so high that Poisoning them is a necessity to fight them or Poison will be horribly overpowered against all bosses.
If Poison can hit a boss, it becomes the only way to play. So we make them immune. Due to the immense total damage Poison can spit out, it'll have to cost at least 75 mana. Yes Fireball does more damage, but only in a small area, Poison hits everything on the map.
I'm almost certain that 5% health is too much damage and would need to be dropped to about 3%, for 30% total. But this would come out in testing.
Frenzy
Gives your towers a boost of speed, letting all of them hit 30% faster for 10 seconds. Costs 60 mana.
Straight and to the point, this one doesn't affect the enemies, it affects your towers.
Preserve Life
100 mana, lose no lives this wave. This is a Panic Button spell, if everything is going bad and your towers are failing. This is an option to keep yourself afloat just a little longer. It also gives the player an interesting choice "Do I use my spells to kill these creeps? Or absorb the damage?" In practice I'd imagine this spell would provide little help, as even if you survive this wave, if your tower damage is THAT low that you needed to blow Preserve Life then you're not surviving the next wave. Most likely this becomes the de factor spell of the last boss.
Potential Issues
This design has a lot of potential issues. Some I've addressed, some I haven't. I'm going to look at a bunch of them and expand upon them, and brainstorm solutions.
Overpowered Spells
The reason spells are added is to give the player something to do during waves. To alleviate the tedium that comes with Tower Defense games and how non-interactive their combat is. But the mechanics I listed above have potential to be too powerful and make them game uninteresting. Obviously a lot of testing will need to be done to verify this, but I still strongly suspect them to be more powerful than intended.
One of these problems is actually the Mana. If the player builds quite a few water towers the mana bonus they'd give would negate the high cost of some of these cards allowing them to be used very frequently. We can offset this by vastly reducing the damage water towers too so they are horribly outclassed at later levels forcing the player to use spells more frequently. This is quite a valid strategy and something I'd like to see in action, but what I'm concerned about is players who build 2 or 3 water towers at most and the rest normal magic/physical towers. Then they're getting the benefit of high mana regeneration without losing much damage.
An option is to remove mana and instead give every spell a cooldown relative to how long it would have taken to restore the mana. Fireball was 55 mana, which at 3 mana every 5 seconds is 95 seconds. So if most of the spells had a cooldown of about 100 seconds, but could all be used at once, you'd absolutely slaughter the wave you're on. But it'll be 100 seconds before anything is ready again. The Water Tower would need to be redesigned to do damage and maybe inflict critical hits, or every shot against a creep does increasingly more damage (Chinese water torture tower \m/ ).
Calling waves
Calling in extra waves seems to be a standard in Tower Defense games, and a good thing it is too. I played some of the earlier ones and it sucked waiting 10-15 seconds for the next wave to hurry up and get there. The question is do we allow players to call in as many waves as they want? Or just one at a time?
Score, Maps and other options
Why play? Why play more than once? What purpose is there for going through it all again?
Desktop Defender on Facebook has competitive scores and difficulties. By killing creeps you get points, by killing them quickly you get more points. By keeping your lives you have even more points. Each difficulty has a multiplier associated with it. So higher difficulties are a bigger multiplier and a higher score. With score we could allow other spells, such as increasing the speed of creeps but granting a higher score for each kill. A good risk-reward scenario.
This could be something to appeal to the more hardcore audience, by allowing multiple difficulties and scaling creep health and number of waves based on difficulty you can give them something to aim for. A High Score. This kind of gameplay also forces effective tower and spell use, the casual player can play on any difficulty and enjoy the game. The hardcore player gets to try and find the best combination of towers and spells to beat all the waves.
Multiple maps is another option. Even if score is not the issue, varying maps will change the difficulty and force different tactics. Bubble Tanks Tower Defense has a map select screen and every map has three shades of colour. Dark means you've never beat the map. Lit up means you've completed the map. Lit up with a white aura means you didn't lose a single life when you beat the map.
The desire to have every map with a white aura is a compelling motivator for replay. It's also possible that some of these maps will be mazing maps, where there is no fixed maze and the player must build towers to form a maze to force the creeps through. It adds a different dimension to the game and some towers which are great on a fixed map, might not be in a maze map.
In addition to this are various game modes.
100 waves - If we have 50 waves as standard, let this one have 100. Double the waves means double the game length and the health of wave 100 will be enormous.
No spells - You only have your towers, no spells.
Fixed cash - You start with 10'000G. You get no gold no for killing creeps, set up your defenses and let the good times roll.
Fixed number of towers - You can only place 10 towers. Choose wisely.
Fixed positions - Only 10 squares on the map can have towers placed on them. Which towers will you pick? Similar to fixed number, but this one restricts position as well as limiting number.
Infinite Waves - They just... keep... coming. How long will you survive?
Night of the Dead - After killing a creep, a couple of seconds later... it gets back up as a Zombie! With full health! But half movement speed... so it's not that bad, except that even as undead they keep all their special abilities. Oh dear lord... Sloth Boss Zombie.
The End
I gotta say. I want to play this game now. Zombie Mode sounds quite fun and it would be interesting to see what sorta of tower setups you'd need to do to take on both the living and dead versions of each wave.
Now... what should I design next...