Wow, the grappling hook and glass panes are genius. As soon as I thought it was over it just kept expanding on the concept and making it more interesting.
The red platforms could pop out a little more but I like how the game looks, it has its own little aesthetic. C, W, and X are difficult to use together but otherwise the controls feel great. Every time I wanted to do something with the grappling hook it pretty much just happened without fighting the controls at all.
You could build an entire game around just the grappling hook! (I mean, I guess you did)