I really enjoyed this! I think it's a game but it's also a communal art piece.
I think the player to player interaction is really fun and creates a lot of opportunities for interesting communication.
The press and hold (and associated wrist pain haha) I think is good at representing the pain of pushing the boulder (sort of). Pushing buttons would accomplish the same thing, but I think a single button would be more monotonous (which might work better?).