I am a bit saddened by lack of controller support and it was difficult for me to control at times, but ultimately I sunk a few tries into the last boss and was able to prevail.
Maybe I missed the instructional text to tap right click to just throw a regular projectile but I didn't discover it until the cave area. Spark itself was great, had a nice risk/reward factor and you could bait a TON of enemies into it. It also did so much damage that I ended up kind of tanking the last boss via potions / attrition, after my dodging skills proved too feeble. Adding i-frames to the casting animation was an awesome touch which I abused a lot.
The boss' attack scripts felt like sometimes he would sit there and let you wail on him for a while, other times he was playing 4d chess and the player was a checkers piece. But that sharp uptick in challenge is my biggest gripe besides the control scheme.
Wonderful graphics and music to round out a very above average effort.