Perfect besides the awkward map and limited save points
I tend to enjoy clearing out all the enemies and exploring every corner of the map, and Aquaria pretty consistently rewarded me for doing just that! Nearly every end of the map contained something worth collecting, and defeating enemies often caused them to drop ingredients for cooking.
High points are graphics, music, exploration, and story. Low points are that you can only save at a save crystal (multiple times I died after exploring for a half hour beyond the last crystal — frustrating) and the map overlapping itself in some areas and not allowing enough zoom. I spent about 50 hours with this game getting all the achievements and collecting everything.
Another strong offering from the first Humble Indie Bundle!