This looks like a solid take on the jam theme, though I wasn’t able to actually fix any pipes myself (but could finish the levels regardless). Admittedly I was playing on my own. If you need two players on a pipe to fix it then that would make sense, but I feel as though I’m having to take a guess as to how to play this.
That’s hardly the worst problem to have, though: it strikes me as the sort of thing that may have more to do with how the game is explained than how it actually works. I see you say “you need two to play” so it’s probably on me for jumping into the game regardless, but it would be more helpful to know why you need two. Setting a minimum number of players to start a game might also help here, though for the jam it’s probably handy to be able to let one person at least have a go on their own. I’m certainly glad I could try it out.
In any case, you’re ten years old and you made an online multiplayer game? That’s really impressive! I hope you stick with it.