Like others said on comments, the game is interesting but it is a bit unclear at first how to construct our monster and send it to the battle.
I liked the music and the graphics are competent but it lacks "juice" for a better visual (screen shake, particles, animation... this kind of stuff)
Good job using a network. Really impressive for a game jam!
One note: I think a bug allow to buy a starfish piece without having enough money (this was suppose to happen?)
Overall, a solid entry! Congrats!