It's hard for me to articulate but I guess you should be thinking, okay, well the Primary Goal of the game is to get to the end of the stage, and then the Secondary Goal (for advanced players and replays) is to get a high score, right? The question then becomes "what kind of play am I trying to reward?"; for example as it is right now there's little incentive to really kill enemies unless you're trying to get a high score, so the primary and secondary goals are a little TOO disjointed (in most shmups your primary goal involves killing enemies because killing enemies is satisfying and if you don't you get overwhelmed by bullets and die before making it to the end of the stage). So what you could do is make enemies a little more involved somehow (maybe have enemies try to target you more or have you need to meet a quota of defeated enemies to proceed in the stage or something). This is, in a basic way, what I mean by the focus thing. I could play the game in my "cowardly way" doing hit and runs and I didn't feel like I was rewarded but I also didn't feel like I was being punished either, so I sat in this limbo where I felt like the game wasn't pushing me to get the most out of it. I don't have much experience with 3D plane games though so I can't suggest much more "detailed" advice unfortunately, hahah, but I hope I was able to be helpful in some way.
Really most of this could be solved with proper level design. Once you start making levels with setpieces and planned hazards and stuff it all becomes more obvious as both a designer and a player; so I wouldn't worry about it _too_ much.
Thanks! This was definitely helpful. If I continue working on this I'll see what I can do about making the enemies more engaging.
Since you mentioned quotas, Starfox64 had an informal quota system, whereby you'd be locked out of certain paths if you didn't get a high enough score but could still beat the game. Of course that would be a bit much to implement in a short game jam since I'd need enough levels to justify paths, but I guess there's no limits on what I can do with this now.
Maybe killing enemies with their weapons could increase weapon stability?
And the level design was definitely a pain point during development. The system I made doesn't actually let me see the levels until I play them (which sounds stupid, but there was a long list of reasons for building a system like this). So from my perspective the levels just look like this right now. Hopefully this is something I can fix, since otherwise proper level design will take forever.
Ah yikes yeah I can imagine that's rough, hahah. My game also has all of the level design be done through code, but since it's only two dimensions it's a lot easier to imagine and visualize and since it's purely "wave based" I can simply set a timer to spawn at any wave any time I want. But for this kind of game I think it'd be better if you were actually travelling through a real location with the enemies actually placed where they would be (besides spawners of course). I'm not too knowledgeable on 3D game development in general though so I don't know what would be most "optimal" but it sounds like it'd be something like that. As for the weapon stability thing, simply having more enemies that try to "get in your way" and improving the aiming would do a lot. You could have boss fights where enemies spawn periodically and you have to sort of "pick" in the moment which weapon you like best for that boss or something. Just throwing stuff out there- I think you're on the right track either way.