Very cool idea, I like the different dynamics of each character and swapping between them and having protect the inactive characters was a good challenge. I think the enemies could stand to move a bit faster to make them feel a bit more alive and ramp up the challenge. Also if you did a post-jam version then adding more of an objective to the game would be nice, perhaps having the player progress through a dungeon, with each room being a unique arena like you have now, I think that could fit the group of heroes theme you have.
Really good work!