In order to win a level you need to complete Quests before you run out of Moves.
A Quest can be, for example, to defeat a monster or collect 13 blue Roomies. Each level can have up to 3 Quests and all the Quests need to be finished in order to win.
You spend one Move each time you slide Roomies and match them into combination of at least 3 Roomies of the same color. If you reach 0 Moves before completing all Quests, the level is lost.