Game Design, Programming and running a one-man games business…

more out-loud design thinking

I’ve been doing some playthroughs of various gameplay modes in GTB and thinking a lot about the game design, and the way units interact.

One of the core things that makes Tower Defense games playable, and casual (to a degree) is the clarity of how units interact. There is often a clear way of differentiating how the units work against each other. For example, gun turrets are good against ground units, lightning turrets are good against flying units, laser turrets are not-bad against both. Often that sort of data is as complex as it gets. You can then have an upgraded ‘level II’ laser tower that is the same, but better, and so on…

One of the unique selling points of GTB is that towers have individual modules that can be combined, so it’s not as simple or inflexible as normal. In theory you could customise your defenses to do exactly what you liked. The trouble with this is it over-complicates things and makes the game less playable for first-timers and casual players.

I’m thinking right now that this is fine, as long as it’s clear what MODULE achieves what, and as long as it’s clear that the different classes of unit (Turret/Mech/Tank/Infantry) still have definite characteristics.

In other words, when you see a bunch of enemy infantry, it needs to be obvious that you think “right, I now need to build tower X”. This is where GSB let itself down.

So… in terms of broad principles:

  • Lasers are good against armor, bad against shields.
  • Ballistic weapons are good against shields, bad against armor
  • Missiles are generally average at everything, but have splash damage

In addition to that, I’m thinking of some hard coding so that:

  • Machineguns are rubbish against everything except infantry, where they are devastating.
  • Flamethrowers are the same as machineguns, plus they have splash damage.
  • Bigger weapons (all turrets, and mech/tank weapons) are relatively poor against infantry.
  • Infantry weapons are relatively good against each other.

That will mean some code changes. In addition, I’m more heavily skewing things so that:

  • Tanks do not have shields of any kind. Tanks are all about armor.
  • Mechs have the best lasers and the best shields.

Plus also:

  • I’m adding in construction times for turrets, so you can’t insta-place a turret.
  • You still cannot destroy a tower and reclaim some of the cost. Is this important? I never do it, but some people do. Not sure…
  • You can design (then use immediately) new units mid-battle. Maybe that is a bad idea?

There are a multitude of other things. I’m of the opinion that pretty much *all* maps should have at least two routes, so when you are placing attacking units, it’s a constant game of ‘aha, I see the right-side route is ill-defended against infantry….’ Obviously the first tutorialish map should be simpler.

I do wonder if I should put together a really early playable alpha of the game without any of the fancy graphics, just to let people play with the mechanics and offer feedback. If the majority of music / graphics aren’t even in the game, I could do that without fear of piracy or people confusing it with a finished game, and make it free. Hmmmm. I just don’t know… Would mean a nightmare load of separating stuff out… I wish I’d thought of that 6 months ago.

24 thoughts on more out-loud design thinking

  1. An Alpha would be very cool to play about with. It would be great if when picking modules you could filter them so that if i was trying to defend against infantry for example i could hide everything that was ineffective, which would stop the combinations being overwhelming. Obviously there could be an option to just have it all displaying but as a beginner it would be helpful

  2. I’ve never been a fan of TD games, but Defense Grid just sucked me in on another level. One thing I noticed as a novice player is that as you got into a level with a lot of towers already placed, suddenly not even following the standard upgrade paths helped combat poor tower type placement.

    The idea of modules is pretty cool in that respect. Say i could choose an adaptive ammo upgrade to the gun that allowed it to be more effective against armor (but still not as effective as laser) etc. I could react to weak areas along the route during waves.

    Also while i never dismantled towers for resources, it was useful when i made a mistake with placement, and the construction and upgrade time in DG was just long enough for a few close calls

  3. re: dismantling towers – i agree that this shouldnt give resources back. However, maybe you could require towers to be crewed to be operational, then you could reassign crew between towers.

  4. I think assigning crew would get frustrating very quickly.

    Regarding modules, maybe you could arrange it so that everything is modular and combine together to create the final turret?

    So you’d have a base that determines the overall size of the weapon (small ground mounts are better at hitting infantry but do less damage due to the smaller weapon, while an AA mount can’t hit things on the ground at all), the weapon type itself which defines what type of defenses it’s good at penetrating (and any special attributes like splash damage), and then whatever other special modules there are.

  5. The end of all this is to compensate easy playing with a lot of possibilities, modules are the best way to do this, turrets should be allowed to dismantle giving back resources, of course but not the original turret value, but lower ammounth. I really dont like very simple td games, i mean just “i pick up this turret, i place this turret, and i watch this turret do its job”, like if it was a TD game of starcraft, i love tower defense games in which u can upgrade, customize your turrets, combine defense powers and attacking powers, buy new tech, and having more possibilites of a diverse game yes, adding crew as another handicap. More things not always mean a more complex game, thats the hability of the creator to mix both in the final product.

  6. Maybe try giving units ‘armor class’ that reduces each shot by some amount? Then machine guns naturally become rubbish against anything with armor but great against infantry, if you represent infantry as a number of small units with low health and no armor.

    Then you could play with weapons that degrade armor class. Maybe shields regenerate too, if the units aren’t under fire…

  7. Alpha – we will test the heck out of it.

    Machineguns are very effective against trucks and at close range the engine grill of a tank (all WWII designs, and some modern). AA is one of the best anti infantry weapons you can field (assuming your AA can ground slew (most do, even WWII german AA did)). Howitzers with shrapnel rounds have multi kilometer kill radius’ for infantry. Tanks all carry an array of anti infantry weapons. Missiles and rockets are incredible anti tank/building.

    Can’t wait to see it :)

  8. Maybe make tear-downs free until you apply the first module? And the more specialized/rigged the tower is the less efficient it is to destroy it?

    Selling is really important to me in these types of games. I’ve noticed two major trends that really bug me:

    Maps give 100% back. I find myself looking at the next wave and then frantically reconfiguring everything. If they let me choose when the wave comes, this takes FOREVER and I am too OCD to not setup the hard-counters every single time. I like the freedom but feel like I’m fail unless I make each wave optimal, and that isn’t fun..

    Maps give like 10% back. Basically if you built the wrong stuff you’re better off restarting the level. I hate this even more. Don’t let me destroy the tower if it’s going to shoot me in the foot, I’ll just click the sell button on accident when things get frantic and I’ll have to start over anyway. If it’s a matter of reclaiming the space, come up with something a little more novice friendly.

    I think somewhere between 75% and 90% are what I enjoy the most.

  9. I’d like to see something that makes me think mid-wave so that I have to issue more intricate orders. Mechs/tanks with reflective shields or magnetic repulsers that that will send part or all of a laser/missile/bullet back at the tower or angled depending on the trajectory. Tanks that take light/heat from towers to generate more power for themselves to increase offensive output. Limited ammunition for bullet/missile style weapons so that they are more of a tradeoff against energy weapons that have to recharge. Tanks that dig under the ground so will need to be pounded at with mortar style weapons.

    Things like these make me reconsider if I want to waste weaponry on enemies that I won’t damage and may damage me and if I need to conserve my ammo for more challenging and specific enemies.

  10. How will damage be displayed? Could integrate instant feedback of damage into this. Ie a red number vs a green number floating up, or the unit flashing a different colour when damage is applied.

    Monsters on PSN used sound effects although I assume that you will have a lot more going on so the audio cue is less effective (also Monsters probably only had 10 sound effects total which made it easy to pick up on what was going on)

  11. early playable alpha game is a good idea for refining the game balance. you cant simply balance the game by yourself alone. let many people play it and give you feedback. anyway, if you dont do that now, you probably will do it postrelease with patchs, based on the feedback of players.

  12. Cliff, can you make turrets have slots?
    So that when you build a small tower you have one small slot.
    There you can mount a machine gun or a small flame thrower.
    Also the turret then has just limited amor and can be destroyed fast.

    The biggest tower could feature one big slot, two medium and one small one and has ‘teh powerz to infintiy’.

  13. I’d like to see a short deconstruction time, during which some resources are reclaimed, but can be destroyed by an attack. I’m not sure about design-then-place, I think it might be easier to do build-and-copy – so you place a turret on the map and add modules to it while it’s under construction, then you can duplicate that design (and change the modules on the duplicate if you’re so inclined, with no extra cost so long as you change it within the build time). That might require a clever way to automagically generate a menu of recently/frequently used designs which makes it easy to quickly distinguish between very similar designs.

  14. “Maybe make tear-downs free until you apply the first module? And the more specialized/rigged the tower is the less efficient it is to destroy it?”

    This. I totally agree :) In the early stages you can tear down and counter unexpected things, but in the later stages when you have to build up your turrets to be more effective it gets gradually more expensive to not plan ahead. It also avoids the annoying situation where you waste money by clicking the wrong thing.

  15. IMHO fun is more important than realistic, unless it breaks intuitive gameplay. For example, designing a tower mid-level is unrealistic (how fast can a factory generate a new product?) but fun, and would be a good addition. Same goes for dismantling/reclaiming parts for cash while a fight is underway.

  16. I actually have a rather important design question concerning GTB:
    Are it’s battles Deterministic?

  17. @Tower destruction: I don’t like this feature (especially if you can claim a large percentage of the costs), since it facilitates arcade / click-fest style of playing. By fast removing and rebuilding you can effectively move towers around.

    @Designing stuff mid-game: Bad idea IMO – there is a time to design, to prepare, and there is a time to test things out (aka battle it out). It might be good with single player games, where you can freeze the game while working on your design, but in real time multiplayer it wont work. Even in turn based multiplayer it will irritate the other players if they have to wait for ages until you are finished designing.

  18. Tower types that are effective against different unit types = only one defense strategy will work – a mix of tower types.

    I want to see some kind of inconnected support structure between the towers, that, by destroying certain parts of, can smash the network. More than simple “Booster Tower – +5% damage to nearby turrets”. Something more.

    I’m thinking on this subject and I am reminded of the game M.A.X. A Turn based/RTS hybrid in which you can build a large base that was interconnected via being adjacent to other buildings and via connector pipes. Resources would be available to the network only if connected to said network. You could cut a base in half by hitting key points, isolating turrets from ammunition, factories from metal, gold ore from refineries etc. I think something like this could work very well in GTB. And it’s so much fun to design a complex base in M.A.X. But so annoying that it took so long and had to be done from scratch every time. This wouldn’t be the case in GTB. And it means the defense side of the game will be as much fun to spend time designing as the attack side, as players create complex interconnected supply chains through drawing pipes and strategically positioning buildings.

    There could even be, more expensive, underground tunnels/pipes to provide supplies – without the risk of loss in combat – a good addition of choice. It also creates a strategic element – where are the supply sources, which are player created and which are pre-placed? (E.g. I placed my ammo dump, now I’ll link it to my turrets. But the oil for the flame throwers comes from that oil derrick over there). This way, turrets can be harder to destroy and an emphasis given to targetting supplies. Without supplies, the turret would run out of ammunition.

  19. I’m not entirely clear on how units work so far. I would assume that the tanks are like the ships from GSB but with one weapon slot. If that’s the case then do the mechs have multiple weapon hardpoints that all face forward on a single rotating torso/arm unit? And if so, will the torso even have 360 degree rotation?

  20. Comment by LKohime
    August 7, 2011

    I actually have a rather important design question concerning GTB:
    Are it’s battles Deterministic?

    Comment by cliffski
    August 7, 2011

    GTB isn’t real time multiplayer at all, just singleplayer and asynch-challenge based, like GSB.

    So, if we run an asynch-challenge will we both get the same result?

  21. Tanks have heavy armor and (presumably) ballistic weapons (good against shields), while mechs have shields and lasers (good against armor)? What are the purposes of these units? I know it doesn’t matter in most of the gameplay modes, but in Pitched Battle mode we’d experience units engaging units rather than fortifications.

    It seems mechs and tanks are natural counters of one another, such that you send in one to kamikaze the other, where it will either almost destroy the target or be almost destroyed itself. I’d figure war planners would make sure they had an armored laser-firer to melt tanks and a shielded ballistic-firer to shred mechs, leaving tanks and mechs to have some other purpose on the battlefield.

    I know, I know, “gratuitous”, but I can’t help myself. >.>

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