Post Load Modification

A Post Load Modification, or PLM, is an object that the game loads in a room after loading tiles and enemies. These are generally objects that Samus can interact with and change some aspect of the room state. Examples include bomb, speed, and crumble blocks, scroll blocks, and green and blue gates.

Each block type used in the game is one of sixteen types:
0: Air
1: Slope
2: Spike air
3: Special air
4: Shootable air
5: Horizontal extension
6: Unused air
7: Bombable air
8: Solid block
9: Door block
Ah: Spike block
Bh: Special block
Ch: Shootable block
Dh: Vertical extension
Eh: Grapple block
Fh: Bombable block