Try as I might, I can't get past the first big crab attack. It one-shots everything and can easily ignore the damage from turrets.
I like a lot of the concepts in the game, having different resources generated by different buildings (including health) makes the econ-based gameplay interesting. The tutorialization is well done except for one thing: At the very start of the game, if you build a shell collector and a turret first, you softlock yourself because you don't have enough snails to make a snail house. Ideally the snail house should be the only thing the player can make until they have at least one to avoid this from happening.
The upgrades are a great addition, however sometimes I'd get offered two of the same choice at a time.