Wow, extremely well made game. It deserves some more recognition. I reached the "end" of the game (I just decide this bottom left corner is basically the end) after like 30 minutes playing it. :D 
It would have been nice if there were some sorts of celebratory rewards for reach max level, or some sort of ending. After playing the game for a while, personally, I would also consider just combining the pickaxe and the sword attack into one action, to prevent requiring the player to constantly switch back and forth between modes.
On that note I think you should also add clearer instructions in your game or on your game page, because there weren't sufficient tutorials on how to play the game. For example, I didn't how to switch to sword and tile placement mode for a while, and I discovered it to be Number Key 1, 2 and 3. Changing the game page during jam rating period is allowed so I would strongly suggest you do it.
Overall a very enjoyable game, well done!