I am not sure if I've ever seen a fighting game with this mechanic before, and the aesthetic that you've chosen, while I realize was probably more for time than anything else, works -really really- well with the game. I think you can easily build on this to be something to sell: this is one of the nicest surprises a game jam game has given me in a while.
I wonder how easy it is to snowball people with how fast you can place traps right now? Is that good or bad? I don't know but I love the core idea as it is right now.