Metroid Prime 2: Echoes/Morph Ball Mode

Throughout the game, you will run into many areas that are too small for you to navigate. In these situation, Press to go into Morph Ball Mode (press while in this mode to stand) and you will transform into an armored ball that can fit in those small places (i.e. tunnels and drains). Find these additional upgrades to expand your avbilities in this mode:

Boost Ball
Hold to build up a speed boost and release to accelerate. Useful for navigating half-pipes.

Spider Ball
Press and hold to attach yourself to specific magnetic tracks, and use  to move across them. You will stay on the track as long as you keep holding. Release it to drop off.

Bombs
There are an unlimited number of these, but you may only lay three at a time. Use these to destroy objects made of Talloric Alloy and enemies. By positioning the Morph Ball directly over a bomb, you can propel it upward into the air.

Power Bombs
Press to deploy these. You will need to replenish these by defeating enemies and collecting Power Bomb Capsules. Destroy Denizum impediments with these. There are expansions to increase your carrying capacity, but they are well hidden...