Flying... what?Yeah. My suggestion: introduce a new enemy type, flyers that can shoot globs of acid just like the spitters.
Why would we EVER want this?Right now, the game only has 3 enemy types (excluding evolution states): biters, spitters, and worms. As we know, worms are static defenses for the nests, but I'm counting them because they can attack.
Adding another type of enemy - flyers - could create some much needed variety here. Obviously their biggest advantage would be ignoring cliffs, structures, walls, and bodies of water while moving (unless traveling with ground forces, more on that below). Their default attack would have to be a ranged acid spit. Even if you see just one flyer, you know there will be more where that came from, so you have to plan accordingly. It would keep players on their toes, because past a certain evolution factor, you suddenly have to watch out for death from above!
Since I saw the suggestion for biters using themselves as landfill, I really liked this idea but thought it would cause too much disruption for the player if biters could permanently create paths through water for themselves - personally I feel that ability should be reserved for the players and using landfill. Flyers could pose the same threat of crossing bodies of water without allowing them to spread bases. In areas with high pollution reaching "biter zoos", it would encourage the player to defend against flyer attacks or simply march in using landfills (or use artillery, or a spidertron) and destroy the nests outright.
Balance concernsSince flyers would directly affect the aliens' tactics and strategy, there are a few design considerations to make them manageable for the player:
- Coordination: Flyers can either attack on their own if crossing bodies of water is inevitable, or provide air support for biters and spitters. They would need to move at the same speed as biters and spitters during joint attacks, to avoid having their air support arrive too early or too late. For joint attacks, flyers would travel along the same path as biters and spitters to avoid splitting up or getting too far ahead.
- Health and damage: I would imagine flyers have slightly less health than their spitter counterparts, but deal the same amount of damage and have the same attack rate.
- Defenses: What types of hand weapons and turrets would work on flyers? Since the player can already mouse over their own flying bots and hold C to shoot them (or spacebar with the flamethrower), I would think any hand weapons would still work on flyers. Gun turrets and laser turrets would probably have no issues either. Flames from flamethrower turrets might still deal damage to flyers, but only take aim and shoot at ground targets, so they would be useless in attacks exclusively carried out by flyers.
- Expansion: Obviously, as a player, killing off expansions and preventing new ones from appearing would be very difficult if flyers could create new nests. The best way to prevent this would be to simply not allow them to create expansions without their ground unit counterparts. This way, nests separated by water and "biter zoos" on islands would no longer be harmless in the sense that none of the aliens could ever reach you, but they still would be prevented from taking new territory.
- Evolution: Since flyers would be quite a powerful threat, small flyers would probably come into play around the same time or a little bit after medium spitters, at around 45-50% evolution factor. In general their spawn probability and large/behemoth status would increase at about the same rate as spitters, albeit with that initial offset. Additionally a new "flyer spawner" might have to show up and be colored blue, in keeping with the current color convention. It would spawn only biters at first, then it would start spawning small spitters when spitters first appear, then spawn flyers from the point flyers start appearing.