Love the idea and implementation. Think I got the ultimate boss? Two Deer ones at least. Can see you must've had plenty of stuff you wanted to implement if we had more time and I think many would be keen to see it after the jam!
After the two deer ones there are three more levels before the ultimate boss but we miiiight have had a tad bit too small of a hitbox on the bigger bosses so they're much harder to merge. The hitbox on the deer is on it's neck... But hey, the deer is pretty strong too!