I liked the balancing act and the effects that happen when you go too low/high in a resource. The graphics were great, sound was good but I think there could be more sfx for the enemies and when you hit something. Loved the dance and UNLIMITED POWER! Very fun ideas! Here are some suggestions I think might improve the game:
The balancing mechanic seemed to reward me for standing still in a small crowd and spamming fire. Since there is no noticeable cooldown on your fire spell and since you're rewarded for getting hit, you're also rewarded for playing in a somewhat boring style. I'd suggest having a way to widen and narrow that bar so that players don't get directly rewarded for getting hit/making mistakes. Have a max resource amount for the bar and every time the player gets hit, shrink that max amount. To recover that resource pool you could use drops potions/glowy things that spawn around the level that give it back. This way when I get hit I can only attack 4 times instead of 8, but my health is still low so I need to be careful.
Then I think you should have two basic skills instead of one for the balancing act, and since this involves a lot of health/mana sacrifice I think a necromancer/dark magic type character fits really well too. The first spell might be a life drain beam that siphons health and drains mana. Then the other could sacrifice health, restore mana, and shoot your blood at the enemy that creates an aoe. I think this keeps the spirit of the mechanic in place but also allows for deeper gameplay. Also you could make each resource give a buff, maybe speed for health and attack for mana. That way the player can choose the one that they want at the time. Then they'll need to balance their resources even more accurately!
Mostly spitballing, but hopefully you get some nice ideas from it :)