What's the minimum you can do to make it fun?
Can you cut down to 1 weapon?
Can you use music with a free license?
Can you use open source sprites?
Can you use open source sound effects?
Can you make it enjoyable with fewer levels?
Can we have fewer enemies?
If needbe you can start fresh. You're 1 day in. Things like ui, game controller, player moment, etc. may all translate to a new game. Good luck!