The most fun one I played so far. Couldn't put way. Just a few comments:
In terms of difficulty, the first level seems a bit too much. I've had almost all the upgrades by the end of first level and was kinda surprised there was another level afterwards
Volume of sound effects kinda low, music is cool though as well as pixel art and aesthetic in general
I love how you have two health bars, one normal one and the heart icon itself for "Last Stand" moments, very cool idea.
Would be nice to have some kind of indication before enemies attack or maybe at least decrease range of their spears, seems unfair your spells go such a small distance (at least before projectile speed upgrades) and enemies spears just fly across the entire level.
Overall Just Awesome