Atmosphere and sounds are really cool. Some details (look down) were already discussed in comments, maybe just one thing to mention: some pipes (vertical) are used as background, while others (horizontal) are used as platforms. At first I didn't realized, that those pipes are also platforms - I think that if you would do different color for "background pipes" it would more strike to the eyes, that pipes are platforms as well (although I understand the time limits of the jam ;) )
Overly, great game indeed!