This whole thing started as an attempt to come up with a better control scheme for flying a spaceship around than in Asteroids; I liked its core economy of choice between moving and shooting, but it felt unwieldy. Rubicon is my response — I tried to preserve that core mostly-mutually-exclusive decision to steer versus aim, but make it easier to switch between the two.
I also looked at Geometry Wars and a couple of the other twin-stick shooters that it spawned. I didn’t learn a lot though, since it allows you to do both simultaneously.
Luftrausers showed me the form of juicy 2D flying + shooting.
I initially tried copying Mechwarrior/Gratuitous Space Battles with slots and whatnot, but it never felt right. The final version was cribbed almost directly from Megaman Battle Network, with my own addition of “addon” components and the bonus for symmetry (there are other shape bonuses too but they’re pretty trivial).
I copied a lot of the weapon/ability/enemy designs from Bastion+Transistor. They do an *amazing* job making equipment “swingy” (no +5% incremental improvements) and allowing different loadouts to generate novel gameplay.
Space Pirates and Zombies did a pretty good job of filling the design space of “what sorts of objectives can you have in a fly-around-and-shoot-things-game”. I didn’t end up using most of it (base defense, hunt, assassinations…) but it was a good starting point. Also, progress past escort missions not depending on the survival of your escort was a good call (you just don’t get their bonuses).
I mostly ended up with two core mission types (and enemy types, for that matter): shooting challenges and movement challenges (cryopod rescue).
PCG mission nodes:
FTL, obviously. Though I don’t like the lack of information in FTL, most of the time you’re just randomly choosing where to go. I pared it down and made things a little more straightforward. The creators of Spelunky put up a cool walkthrough of how their PCG engine works, which I based a lot off of.
I actually played around with making it a roguelike (contact enemies to zoom into battle mode) for a full month before scrapping it (KILL YOUR DARLINGS) as an uncontrollable too-complicated metastructure.
Randomly-triggered banter? Sounds like Bioware.
Badly translated English? Sounds like Zero Wing.
Unlockable stuff from the main menu showing up playable ingame? Sounds like FTL and Crypt of the Necrodancer.
Ever since I read Kidd Radd (a semi-animated online webcomic epic from 2002 – 2004), I’ve been conscious of games about violence for the sake of violence… whiiich is basically what I just made. The muddled morality that pops up in the game stems from this.