Cool stuff! :)
+ Satisfying gameplay!
+ Cool mechanics (Bag getting heavier with more load, wall jumping etc.)
+ We too made a game about digging up treasure so the concept really resonates ;-)
- Small mishap to fix: For QWERTZ (keyboard layout) users the dash isn't Z but Y (since that's your QWERTY where Z and Y are switched!)
Great stuff, cool game you made :)