I like the controls, and collisions work well and smoothly. (something I never expect from first games)
It feels good to shoot monsters, unless you are too close to them, then it just looks like they disappear. Some sort of effect when they die would be a nice reward, and would provide reassurance that you got them.
I enjoyed the little screaming ghost walls. You may not call yourself an artist but those were pretty creative and cute. It was nice to see that an ice prison does not only contain normal boring ice bricks.
I first died by being shot by an Easter Island head. I didn't know they could shoot until one creamed me. He could use some sort of anticipation-- even if it's just his sprite flashing white a half second before he shoots.
On my second run I encountered the little purple snots. I've never been a fan of the lots-of-little-tiny-spawning-enemies. I hate them. I'd be fine with them if I wasn't forced to kill them before progressing.
What if sometimes enemies dropped a key that would allow you to pass the purple locked doors? A strategy could be to save the key up until you encounter the purple snots and then just run to the next room.
I see what you mean about the limited rooms. I very quickly felt like I was running around in circles, and felt like it was hopeless.
I'd like if it there was an actual way to escape the ice prison, since the game prompts you with that goal at the beginning. Maybe some hints or clues as to the right ways to go if you end up going the wrong way.
Keep it up! A solid start.