Nice and fun game I had a great time playing it, Aesthetics and music are fine, I would have added more sfx in particular to give feedback to the player when he is being hit.
However I feel the difficulty scaling should be adjusted: is way too easy to become invincible by putting enough points into fire rate and power, maybe you should implement a level progression in terms of points to spend (eg 100 for level 2, 125 for level 3 etc).
Also I found spending points in acrobatics worthless because, again, with enough fire rate and power there is nothing that can stop you and, while it is very satisfing being a mage god, it made me loose interest. Finally, I think there should be an automatic difficulty scaling even if you don't die, or the game can easily become stagnant.
Good job overall!