Nice art and music. The background was glitching out which was a bit distracting. I like the idea, it is very ambitious. I just didn't find a use for combining different elements together. The 3 enemy types had weaknesses : 1. water-water, 2. fire-fire, 3. rock-rock . Not using other combinations was a bit of a waste. Also, it would've been nice to see the elements impacting the behaviour of the gun in meaningful ways, for example fire-fire shoots fireballs, fire-water shoots a cloud of hot steam etc. The maps were a bit too big, in my opinion. I spent the majority of the gameplay trying to find that last remaining enemy. The enemies themselves didn't pose much of a threat and were easily defeated, which isn't very exciting. I think smaller maps with more and tougher enemies would've made for a more fun experience. Despite some problems, this idea is pretty great. The game that you've made is good, but has the potential to be even better.