I cannot play more than one single player game at a time. Right now I am trying to get through Final Fantasy V right now.
I have no clue how people are able to play more than one game. When I start a game I just want to play until the end.
However I can play a single player game + small games all the time. (If I have the time)
For instance right now I am playing Final Fantasy 5 as my main game. Splatoon 2, Puyo Puyo Tetris and Binding of Isaac I play on the side. I can do this because I can play a tetris game anytime for 10 minutes or so. Same goes for the other games.