One of the simplest games I enjoy immensly is Tetris. despite how simple it is, I believe there are a few key game architectures here to point out. First there is the classic interaction loop with a single piece falling down and we need to place it on the grid to clear out some horizontal lines. Then there is the bigger arc of every level, where the game gets more and more intense. In terms of skills, there are few things to do (rotate, move and drop), although we can also perform complex things like sliding on the drop to fit under a piece. There are also a few power plays that are infrequent (clearing out 4 lines in a row with a line piece). This is not a combination skill but rather an infrequent interaciton that adds a little more spice to the game.