Thanks for addressing some issues you had with the game!
The scoring system itself is fairly straightforward, though it's mainly the combo system that is responsible for giving you bonus extra points if you're precise with your shots or not. Still, this system is indeed not very well explained nor motivates the players to use it, so I'll be sure to put more in-game focus on this scoring mechanic!
I agree that the controls, as they are right now, are not very well explained, and that was mainly due to the 2 player coop having both their own keymapping. Still, I'll try and find a better and clearer way to instruct the controls in a future update!
The credit input is more or less a way for players to give themselves a challenge by choosing how many credits they'd want to play with, and it was also a way to strengthen the 'arcade game played on emulator' vibe (like the Neo Radium screens, taking inspirations from emulators like Kawaks, Nebula, MAMe, etc.). So for the moment there are no plans to change this aspect of the game.
Still, I really appreciate your in-depth review of these apects! Either way, more changes will come in the future to make the game more and more accessible for players while also staying true to the arcade/emulator feel of it 👍