Key Basics
The keys are just one type of collectible content scattered across every level in "LittleBigPlanet," however the ability to unlock additional levels makes them the most rewarding. Once the player discovers their first key on the Get a Grip level, keys can be found in all future main levels. Main levels are any level unlocked simply be completing prior stages, without the need to find a key. Levels can contain multiple keys, with each level capable of unlocking two or three special stage levels.
Reward Stages
The reward levels unlocked by discovering keys offer a wide range of activities to participate in, however they can be categorized into two distinct types of reward levels. Some reward levels play similar to the game's core levels, with the players attempting to guide their sack boys through the level from the start gate to the closing platform. Other unlocked stages are mini games, such as the tie skipping mini game unlocked by the first key, which challenges players to jump over a tie as many times as possible without being knocked off.
Key Tips
Although some keys are easy to find and out in the open to be discovered, other keys require a bit more ingenuity on the part of the player. In order to ensure that you do not miss out on keys in the main stages it is important to thoroughly explore every stage as you progress through it. Remember that boards can extend as far back as three rows in some places. Often keys are hidden in locations which require the player to climb up high with the use of blocks and swings, as well as duck behind what appears to be the background but is actually just a wall set up at the back of the second row.
Play Trophy
Playstation trophies are rewards a player receives when playing Playstation 3 games for completing in-game objectives. The Play Trophy in "LittleBigPlanet" is attained by acing all levels in the game. To ace a level a player must complete the entire stage without being forced to restart at a checkpoint. Many players have grown frustrated at not receiving this trophy after acing all of the main levels. This is because in addition to the main stages, the player must ace all of the standard-level type unlockable stages, meaning thorough key collection is a requirement for this trophy, as you can't ace a stage you haven't found the key for.