Category: game design

There are so many flavours of tower defense.

I haven’t seen another TD game with a minimap yet, but I’ve seen them (like Defense grid) with a ‘forecast’  GUI that shows you what is approaching. I quite like the forecast bit, because it creates an emotion of panic or dread, and emotion is vital to games. I haven’t decided to implement a similar feature yet (and anyway it doesn’t matter for attackers), but I am intrigued by it.

Minimaps aren’t normally required because TD maps are often small, but mine are big, and I think a minimap is very handy, especially if you have a big screen and can afford the real estate. Plus, the minimap will toggle on and off anyway, so it would be silly not to put it in, as it’s all coded etc.

GTB has fog of war, so you can only see X pixels radius around your units. I like this, I like it a lot, but again, I don’t see it in other TD games. My variety is a constant FOW, so exposed areas return to shrouded entirely once the unit that illuminated them dies. I like that too, but YMMV. Right now you can toggle it off, but that may change. Maybe I’ll force it on when playing challenge maps.

GTB has instant building, so far…. I may change this. I know that it’s a big part of some TD games that you need to plan ahead and get those towers built before the enemies get close. I’m not sure whether I want to add a construction delay or not. Possibly….

I’m pretty sure there are a thousand other decisions like these, and as with all decent game design, you can never really know what the right decision was until you have implemented both ideas, tried them a lot, and asked a few opinions. Obviously that takes extreme time, and extreme effort. I’m beginning to see that having a nice spangly engine with cool explosions and effects is only a small chunk of making this game…

I’ve been away on holiday!  Whilst sitting in the sun, (in the UK too…woot), I read ‘The Design of everyday things’, which is an old, but great book. It has nothing in it about game design but nevertheless I found it inspirational. Mostly the book complains about doors, phones, windows and other things that often get strangely redesigned to be inferior, and impossible to use. It was fitting, as I stayed in a hotel that had some of the worst usability design imaginable. A computerised fancy-ass lighting system that lets me select ‘relax’ or ‘ambient’ but doesn’t let me have 1 bedside lamp on and 1 off, and isn’t even consistant. The lighting had coding bugs…. Also the phone was unusable, and the idiots running the place tried to overcharge us. Grrrr. At least the food was awesome.

Anyway…

One of the points in the book is that usability is partly tied to giving feedback. A good switch turns on a light when you press it, or at least clicks, so you know something happened, and hopefully, what happened. In reading endless rants about this, I concluded that the lack of feedback is one of the BIG design mistakes in GSB. It’s all very well being the case that experimentation and tweaking is a bit part of GSB, but how clear is it that weapon X does Y damage, and that weapon A is better vs shields than weapon B?

Given this, I think a lot of careful thinking is required to get the design of GTB right. Some things I am considering:

1. Making shields a Mech-only item. Tanks don’t have them. Nor do turrets. They look best around moving mechs anyway. This keeps things simple.
2. Weapons do different damage vs unit types in some cases. Specifically, flamethrowers totally massacre infantry, but do little or no damage to anything else. The same is true of machineguns.
3. You fight shields with lasers and armor with ballistics. Maybe lasers do 10% damage vs everything but shields, and ballistics are the reverse. There are no fancy exceptions. Fight an army with mechs (and shields) and you need lasers. Otherwise, you use ballistic weapons.

This would, I think be easier to remember, and still make quite a lot of sense. I can’t see a problem with it, because many tower defense games have used similar restrictions. Some towers battle flying units, others ground, others both. In any event, I intend to do a lot of thinking and experimenting with these mechanics before I spend any more time worrying about any new features or any graphical fluff.

I’ve been giving a lot of thought to the different game modes in Gratuitous Tank Battles. Here are my current thoughts:

Classic (Tower Defence) Mode

In this mode, you play a standard tower defence game. The enemies come at you in pre-scripted waves, and have to get across the map in sufficient numbers to win. When the final wave ends, the player has won. The player earns supplies for shooting down incoming units, and spends supplies by placing new turrets and troops in one of the many pre-defined squares along the multiple attack routes in real time.

Reverse (Tower Attack) Mode

This is the same, but swapped over, with you as attacker. The player earns a steady stream of supplies over time, and these supplies are spent on new units. The supply level is capped, so you can’t just sit there for ages and not place anything, as you waste potential troops in that way. The victory conditions are just like classic mode. This requires a fair bit of AI by the defender, who will intelligently (I hope) place defences along the routes that are most under attack, and select defending forces that balance out, and can best deal with what is being thrown at them.

Assault Mode (attack OR defence)

This is a mode that will also work online in challenges. The player, either as attacker or defender, has a fixed budget to build up an entire army in one go (or for attack, possibly in a number of separate waves). The army then tries to storm past all the turrets without any interaction by the player. The army can be uploaded as a challenge either by an attacker or defender.

Pitch Battle Mode

This is like GSB, but without any pathfinding :D Essentially the maps series of paths meet in the middle and big armies start at one end or the other, marching / driving towards each other and blasting away until one army is destroyed, or everyone is out of range of each other. The last (or biggest) army standing wins. This can also be done as an online challenge game. This is the only mode where both sides have moving units.

Of course, it’s impossible to really say which of these game modes will really work, and which will suck, A lot of it depends upon the exact implementation and numbers. I really think I should implement at least this list though, and give them all some decent testing before deciding if they work or not.

There is SO MUCH to do.