This was a very enjoyable experience. The world was well routed and did a great job teaching me how to use the items I collected along the way. The muffled audio underwater was also a nice touch.

As for feedback I think it would feel rewarding if the sword impacted some enemies in more ways than just dealing damage. For instance the whale creatures could delay their ascent for an extra second after being hit or the frogs/mice could be knocked back. Energy could also build faster on enemy kills. The gun is so fun to use, I'd like to use it more.

I really liked this! Level design, graphics, sound were all really well done! I had a lot of fun playing this. I think the only real thing missing was a "story" but you have the bones of something really fun.