Backtracking After Area 2

Walkthrough: After obtaining a few new weapons in Area 2, you might want to think about heading back to Area 1 to collect some of the items from the newly accessible areas that weren't previous available to you. You won't be able to get all of them just yet; really, there are only two more Missile Expansions to find at this time.

Missile Expansion 1: In the small lava room in Area 1, cling to ceiling. Scale all the way to the top to find the Missile Expansion.

Missile Expansion 2: Just above the elevator leading to Area 2 is a hallway heading to the right. Hang from the left ledge and shoot a missile to the block in sight, then head inside the passageway. Use your Super Jump to reach the next higher ledge, giving the door you come to a shot from your Wave Beam. To get to the Expansion, use your Spring Ball to leave a Bomb next to the wall with weak points.