Hey i'm back again and in user experience i know that you want your game to be fun and not boring. The game should be fun and colorful or creative to make the players to play the game. You should want the game to be challenging so they keep playing it to win or complete the level. For example, the game should have lots of colors and fun entertaining add some effects maybe.
In my games one is a platformer and the other is a chase game in the platformer its a jumping game where you can jump. The chase game is people chasing you and you earn points for evading the other sprites and not getting caught.