Didn't get to try this out since I didn't know this would be multiplayer only :P
On the itch.io app the install isn't working btw.
Howdy, thank you for letting me know about the issue. I tested it and got it to install from the itch.io app, but do let me know if still does not work for ya.
The game is more recommended for multiplayer but you can still play on your own, just press the host button and start the game, and you can play a quick instance of spleef on your own. Do note, when the game begins, you'll have about a 5 second grace period before the ground below will start to give out.