I am generally not a fan of sliding puzzle games, but am a fan of games by Maciej Targoni. Hook and Klocki are two of my favorite games, so Up Left Out was worth a try, at least.
And it turned out to be a surprisingly fun game. The game employs a fresh take on the sliding puzzle mechanic and, of course, has that pleasing interface Targoni is so good in creating, making Up Left Out quite engaging.