Lots of fun, well polished, cute pixel graphics. The amount of screenshake felt just about right, nice sound effects and a fitting soundtrack.
I would add some extra feedback or particles for sprinting. The small line in the top left is barely visible. Also it would be cool to regain some health (Cut those cute flowers maybe?) And an ultimate weapon would be cool to clear the whole scene every now and then to have a short time to breathe :)
But this was a lot of fun. Loved the sledgehammer!