First introduced in Learn the Rules , Clusters are used to purchase upgrades to your Super Powers, similar to Cache being used to buy character upgrades. There is a total of 1255 Clusters in the game, which are scattered about in Steelport. However, some clusters are actually three-in-one, which are the hidden ones that require the use of Powers.
Speaking of which, there are two kinds of Clusters in the game, single ones that are just sitting in the option and hidden ones. The hidden ones will require you to use one of three powers in order to make them appear. Ones hidden in walls require the Blast power, while those in balls require Telekinesis and the ones in the ground require Stomp.
It’s best to wait until you rescue Matt Miller during the story mission, Matt’s Back , to start collecting the Clusters. This is because his side missions unlock upon completing that mission and the reward for his first one, The Pledge , is the Collectible Finder. This pinpoints the location of ALL collectibles on your map.
Whenever you look at your map from the HUB, you will see that you select Collectibles on the big map, which will highlight all of them and make them easier to find. The Clusters use the icon similar to their shape in the game, which is a blue symbol.