Moles rejoice! And this mole even can dig! My cannot -.-'
The hitboxes and fights are quite weird, and jumping like on the moon is also maybe not best solution. I was once almost killed but I was doing an attack immediately after last hit. Something glitched and I was invincible for the rest of the game.
The boss felt very weird but i think I get it: you just have to wait for the biting to end then you attack. Though I have to say you have to attack a lot, it would be very hard without invincibility.
The mole has cool animations;)