This was really cool. I thought the overall aesthetic of the game was really interesting and well done (the entire game felt cohesive), and the core concept was really interesting. Making multiplayer functionality was also really cool (though unfortunately I have yet to be able to try it out).
That being said, the game isn't perfect of course. I do have some feedback:
1. I really wish the game had sound. With the right background music and sound effects, I think you can sell the chaotic and fast-paced feeling it seems like you're going for a lot better. Obviously, it is a game jam, so it's hard to fit everything in (and you probably spent a lot of time making the multiplayer mode), but I do think it's one of the first additions that need to be made if you do update the game at some point.
2. More file types would make the game a lot more fun. My run lasted like 7 and a half minutes, and, by the end, I did find myself getting a little bored just clicking through. Having more file types with interesting minigames to go with it would make the game fun for a lot longer.
3. I know you have the Binding of Isaac like tutorial on the first screen, but with the stylized text and images, it was really difficult to read. I think some sort of more formal tutorial or help screen could be really useful, as I'm not sure I would've understood the game without being at the showcase.
Overall, really well done. Making a multiplayer game in a game jam regardless of my earlier complaints is super impressive, and I really hope I get to test it with people at some point. Great entry!