This was great! I enjoyed the maps and enemies, and I think you did a really good job on the boss, it was reasonably difficult but very fun to play against!!
The artwork is very nice too!
The only thing I would recommend is just that the darker blocks are the ones that can be mined(it might not be clear to newer players) and where the player can move.
Unfortunately I couldn't rate on audio as I couldn't hear any, but apart from that really good job on this!!