For the dust effect, it would help me by better seeing my horizontal positions for jumps I did successfully so I know roughly where to jump in future.
The autojump I noticed and it was actually kind of annoying :P
Do you pick 2 random levels out of a pool of possible levels for each trip to the mines right now? I thought that was pretty cool, it's like a roguelike structure but instead of the entire game being a roguelike, each single trip to the mines was like a mini roguelike experience.
Edit: Oops, should have read the comment above about the random level selection.