A few comments. Hit detection when shooting enemies seems to be buggy when there's and incline. I also had a chrome error where the page was reloaded b because it was using significant memory and interrupted my progress.
@Mimerme, thank you for your comments. You're right about the incline, I skipped this thinking it wouldn't be much noticeable, guess i was wrong about that.
I'm sorry you lost your progress. I tested the game on 3 machines and didn't encounter this issue. For everyone else trying the game, there is also a desktop build available.