A lot of the free games also have DLC for sale. If you play the free game and enjoy it, odds are that it is cheaper to get the DLC on epic instead of buying the game and dlc on steam. No idea how often that works out for epic, but it’s one way they could make money back from free games.

Nah if you only build a 2D structure, you won’t have to worry about the water pressure because your structure will likely not be able to interact with 3D matter. It’s genius engineering IMHO.