I recently started the development of a Tower Defense Game, called Sphere Code. And I would like to know your opinions on Tower Defense Games.

• Do you still play them?
• How much do you like this genre?
• What was your favorite Tower Defense Game?
• What were the biggest mistakes you seen so far in TD Games?
• What makes a good TD in your opinion?

Thank you for participation in this discussion!

Its been a while since I have played

I like them. They are very entertaining. I remember playing some as custom starcraft maps and put a lot of time into that.

Plants vs Zombies would be my favorite tower defense game. It certainly doesn't fit the mold of most tower defense games but some of the ways it varies from the norm is why I like it.

I think most tower defense games don't much to let you counter different types of enemies. Many don't let you know what is coming so you have to blindly make decisions or memorize the order of waves by trail and error. Many don't really have different kinds of enemies, just varying amounts of health. I also think many end up with a dominant strategy where you each level has a single solution that is obviously the best. Again, it often comes down to trail and error. Many of the games strategy simply comes down to determining the optimal places to place your turrets, other than that there aren't many interesting decisions to be made.

A few things I like about Plants vs Zombies. It lets you know what zombies to expect before each wave, this lets you prepare for that zombie type. There are many zombie types that are more than just a higher damage zombie. Each zombie type has a hard counter, magnet shrooms for buckets and football zombies, tallnuts for pole vaulters. The game has enough unique plants to let the player experiment with different strategies. A few strategies I like are using gatling peas with torchwood to produce a high damage per second. You can also you slow peas or blue watermelons to slow down zombies to allow for more damage over a longer time. A row of corn launchers is a fun one. Using onions to force zombies into only a few lanes full of spikes surrounded by gloom shrooms is also effective. There are probably many other strategies I haven't tried, that the freedom to play around with different ideas really adds a lot of replay value. One thing it lacks that I like from other tower defense games are the long winding paths that can very greatly between levels. I definitely see how that would not work in that game, but it would be fun to see a tower defense game that had a depth of strategy with interesting decisions like plants vs zombies, but with long winding paths that would vary greatly from level to level.

I think an often underappreciated aspect of real time games like tower defense is having a good camera AI. In a real time defense game it can be frustrating for players if they're unable to see all the defense locations simultaneously, though it does depend what sort of feel you're aiming for. If you want a punishing game then sure, send a fleet of heavy tanks to an off-screen barrier while the player is already occupied with battle elsewhere, but a lot of players feel like that's the computer cheating. Tower defense are primarily about giving the player adequate warning about what they have incoming and allowing them to allocate resources based on their estimates of what is required. Level design should think about the distance from where the player's defenses will be to the enemy spawnpoint in terms of the time it takes for enemies to get there. This is the amount of warning they get. The more they build their defenses out the less warning they get before combat begins. Making quick enemies weak and heavy enemies slow is a way of shortening and lengthening the amount of preparation time you're handing them for the task you're giving.

Both of you mentioned important points, like

• various enemy types
• depth of strategy (several good strategies instead of one dominant strategy; level-depending; experimenting with combinations)
• enough spawn/wave information, sufficient view to allow a proper preparation

Tower Defense is a part of the strategy genre and strategy is the heart of any TD game. If the strategy lacks of depth or it's hard for the player to develop strategies (less info) the game lose it's attraction, because it fails at its core (of course there are exceptions, e.g. if a TD wants to be funny only and this is the entertainment, not the strategy factor).

This means, that the game design shall focus on optimizing both the depth of strategy and the "tools" for the player to accomplish possible strategies.

And this are the next questions,

1. What expands the depth of strategy?
2. How can we improve the display and the "tools" allowing the player to make cool strategies?

I will post my ideas too, but I will let you brainstorm at first. Thank you for any replies. :)

1. Depth of strategy is best increased by having interesting combinations. For example, turret A and turret B my be okay on their own, but when combined they are much more powerful. You also want to make turrets counter specific enemies, but ideally there is more than one way to counter it. That lets the player choose a tower that best fits their strategy. This is a very tricky part of game design but if done right it can really make for a fun game. Another great thing to have in a game is some sort of risk reward system. They player should be able to choose something that has a higher risk of failure, but if they succeed they get a higher reward.

2. The player should never feel overwhelmed with options even though you want to give them many options. This is best done by incrementally introducing new gameplay elements into the game to create a gradual learning curve. Your towers and enemies should best convey their behavior based on appearance as much as possible through its design or attack animations. Any text descriptions of what things do should be kept very short. Most people aren't willing to read a paragraphs of text to learn how to play a game. If its clear what is happening when an enemy or turret attacks then the player can use that information when developing strategies.

Hi HappyCoder,

I agree with you and this are good points! I want to dive into them even more:

1.) depth of strategy

a) the openness of the strategic approach (offer different possibilities to win, so the player can experiment and do it his way, without damping the challenge)

This is will be very complex and difficult to control (like you said), especially if the game gets more complex in later levels. I wonder if it can be solved mathematically, so you can actually compute how many good ways (sorted by quality) there are to run a level successfully. Basically it would be a simulation of all possible actions combined and then analyzing the results. May take some time to compute for one level, but it should be possible - and would be a good help for designing a level and the level progression.

b) a risk reward system

I was also considering this idea and like it very much. It makes the player's decisions even more important, and that is a good thing in general. In my game you have a small group of "heroes" (special drones), which you need to both build defenses and activate objectives to complete a level (level progress is not defined by wave count but by unlocking the objectives). However, a Sphere can only do one at a time (building, moving, activating). The activation progress on objectives can be stopped and continued. Those Spheres are important and valuable, if they get destroyed by enemies they are gone for the entire level and have to bought again, and you won't have much credits to do so. Often you will have to take high risks in (re)positioning Spheres to build up defenses and activate the crucial objectives. There will be also optional objectives which will unlock new upgrades ... will you take that risk seeking them? Because waves will get stronger by time. I hope I didn't explained that to complicated and you can grasp the idea :lol: it's a nutshell, and even more could be said on this game mechanic.

2.) Learning / tension curve

Totally agree with you on the learning curve. And here is a problem to solve, its' the amount of information. Like you said, few people want to read plain text and don't want to compare tables of numbers. On the other hand, a TD without real stats (and you have to guess) is not satisfying in my opinion. So maybe we can show stats but reduce their format: Instead of Armor: 120 we could display Armor: XX--- (=2/5) ? What do you think?

Thanks for your input :) much appreciated!

On the other hand, a TD without real stats (and you have to guess) is not satisfying in my opinion. So maybe we can show stats but reduce their format: Instead of Armor: 120 we could display Armor: XX--- (=2/5) ? What do you think?

I agree with that. I few stats presented well in an organized way would definitely be useful. As long as you don't overwhelm the user with information I see nothing wrong with that.

Thanks Shyr for the input!

More importantly, it's almost like playing an idle game because it doesn't require much gameplay beyond buying or placing units. And you spend most of your time watching the game go and interacting with it if necessary.

In most TD this is true. It gives you time to enjoy and analyse your defenses. However, I'm not against doing more than placing buildings. My game will be more a strategy type of game with TD elements. That's why I also look out for more then the classical game mechanics, but want to stay connected with the original idea.

Do you guys know some good hybrid Tower Defense games?

What are you thoughts about randomness in TDs ? (accuracy, critical hits, ...)