I love the main mechanic. It's a creative idea that you executed well and plays well. It would be interesting to see how you could advance the mechanic to make things more interesting through-out the game. Maybe you can't capture certain elements if you are already holding a conflicting type - causes some sort of blow back and damage to the player. If I had to nitpick anything, it would be that it felt like the amount of damage necessary to kill each enemy was random? Some would go down with one return shot, another (of the same enemy type would take 5). Small but something I noticed.