Each level contains a number of "score bubbles", which may be collected to increase the player's score to beat their own, and other players', high scores. Users may collect larger bubbles known as "prize bubbles" which contain collectable items. Many of these bubbles are hidden or are in hard-to-reach places, and contain items such as new stickers and decorations, or new materials and objects that may be used in the "Create" mode for the user's own levels. Certain stickers, when placed properly, trigger events. Special clothing and accessories for the player's Sackboy is obtained by completing a level without losing a life, also known as acing a level. In addition to the prize bubbles, collectable keys found in main levels unlock new mini-levels with unique goals, such as skipping a spinning pole or bouncing to grab bubbles. There are also unlockable time trial levels such as bobsleigh racing.