I like the idea of this game a lot. The progression system is also quite interesting, though I'd have liked some upgrades that didn't push up the damage for skills, due to how easy the enemies are to kill.
On that, I feel like I'm perhaps missing something, but the enemies seem to carry over from the previous day with their health, so it quickly becomes seemingly impossible to not kill them over time. And then the next enemy type is even easier to kill. So I had a lot of trouble not losing and having to restart everything.
I'd have liked to see some mechanic that lets you heal the enemies; just a way to manage the HP of these enemies more, since it currently feels a bit out of my control beyond just reducing damage through upgrades.
(Also, the hitbox for the bit seems a bit weird; sometimes I bump into the enemies without biting them, and other times it bites with the tail, or it just bites while they're still quite a bit away from me.)