The push-pull waves, resource management and imbalanced design kept me engaged.
A pain point was the pathfinding breaking in some key points (gaps and bridges).
The first 5 minutes are a bit boring with nothing to do. (Maybe there is a way to make it more intersting without increasing starting resources).
Personally it was a humbling experience for me because I flied through the level on the first try but then got destroyed when the last area unlocked. I had to learn to pace myself and consolidate before moving on.
I would love to see this expanded with more variety and fine-tuning.