BUDDY & COOP MECHANICS
Press [Right Stick] up or [Shift] to call Buddy in single player mode.
On CoOp, you can assign the camera to Buddy by pressing [Right Stick] up.
Hold the [Jump] button to scan objects and wall structures. This will give you clues about how to interact with objects and which walls are breakable.
Hover over an object and press the [Steam] button (RB) to lock it. Use the [Fire] button to apply telekinesis. If Buddy is over an object, he will pull, if he's under an object, he'll push. To rotate an object, press the [Jump] button. The rotation direction will also depend on Buddy's position relative to the object and is indicated by the plasma stream.
Upgrade your hacking level by collecting Corridium protocols.
Scan an enemy to determine its hacking level.
Hold [Fire] to load a hacking protocol and release to fire the hacking seed.
Rotate your hacking protocols with [RT]/[LT]
Use the environment againgst your enemies!
BLOCK BUILDING & CO-OP SPECIFIC MECHANICS
CoOp mode exclusively allows Buddy to create blocks and alter the game's level design.
Buddy's slingshot-like hacking seeds will also inflict damage on non-hackable enemies, enabling Buddy to actively engage in combat situations. Also, many bosses will expose a CoOp specific weak point.
Those CoOp specific mechanics will fundamentally change the game's balance and feel, allowing for CoOp speedruns as a very unique take on the Metroidvania scene. Bock building is not allowed in certain key rooms though, where Buddy's blocks will be destroyed by guarding turrets.