Really unique mechanic. Summon minions/restoring mana via the magical swan is such a great idea.
I did encounter some issues when playing though. It seems that after time, one of my attacks just doesn't work anymore. In one play-through, both mouse button no longer works after some time, and in another, right click doesn't work. Mana was full in both scenarios.

Fun game, I really liked the visuals and the audio made me nostalgic for old flash games. The difficulty balancing felt a bit off -- the enemies seemed way stronger than the swans considering how many enemies spawned. I think they could use lower health pools -- maybe around 5 so the AOE could one-hit kill them. I also think you regain mana too slowly and don't get the chance to use specials as often. I think it could be a lot of fun with more upgrades; maybe ways to make your summoned swans stronger.