Nice graphics and atmosphere! The grappling could feel snappier. Perhaps show the rope go to the wall and have a sound for when it hits?

Got to a max height of 255
*Edit: actually I beat it. It was really good.

The game is slow and unresponsive. I am getting around 15-20 fps and I have a pretty good computer. It's controlling so bad I couldn't do level 1. I think it's because it's on web. Games of this sort should be downloaded onto computer. It must be to heavy to be played on browser. Looks like a very nice and complete game though. If it ran well I am sure I would like it.

*Actually it ran terribly on only level one. I tried a few others and they are better (still not perfect). Although, they are insanely difficult.

Very nice. I like the art-style. The sprites are really well made. The music fits well and the sounds are nice. Good take on the theme too. I find the platforming hard though. Double jumping onto some platforms takes me way more tries than it should. Also it's hard to tell whether a hole would lead to my death or to another room.