I played, won on the first try, but liked it. Actually, if I don't plan to invest that much time into a game, I prefer it to be not that hard: this one could be a little more difficult though. Nice building around a theme... story... whatever.
The most obvious thing to notice is the combat system. I understand we seek alternatives to bump-into-enemy system. In later floors I noticed that it does require some strats, but it can never surprise you, right? I think that surprise/uncertainty is an important aspect of combat.
Also, using combinations like ctrl+h can trigger some browser shortcuts like showing history in Firefox. Maybe it can be prevented in JavaScript by calling event.preventDefault() or something.