You are totally right in that most local multiplayer games have odd controls for keyboard. I usually steer away from them due to that fact but this one drew me in with the art!
Upon some testing on my end, I think I would add the option to customise your controls to fit the set up you feel is best or even including a few different variations (For example I have larger hands and so having my hands bunched up was awkward so I would have set my Player 1 jump to space and shoot to E or F). It's tough because with local multiplayer it almost assumes that at least one player will be using a controller (Which I don't have so this could have been a lot better with that admittedly).
Yeah, I had to choose between rebindable controls or controller support and I think I made the right choice because playing with controller is really fun, even though the comments would probably prefer rebindable controls because its hard to get to get the effort to get a controller (if you have one) and a friend for a jam game lol.