I finally got around to setting up my PineTime. It includes two games, a pong like game and 2048. I've never really looked into how to play 2048. The pong like game is single player. You are just trying to keep the ball from leaving on the side you are protecting. It's not particularly interesting.
I'm not sure how complex a game you can make on the device. I was thinking an infinite runner with only a jump button could work. Maybe a simple maze exploration with directional input. It is hard to select things on the small screen so large input areas are better.