Most of the movement tech in this speedrun are intended game mechanics. Many started off unintended like slam storage and punching your own bullets, but they have been kept in the game because they're cool. Like Celeste, the game will not teach you about it until later in the game, heck, the game doesnt teach you how to do a dash jump until 2-1, but there's a lot of good dash jumping levels in Limbo. In game tutorials for some mechanics will likely be added in later acts, but for now, watch runs, read the guide, etc.

Other things like the 1-3 oob is not a glitch, but an abuse of the game optimization deloading the room and the door close radius not being small enough. Skipping enemy arena triggers is also not a glitch, please skip the 0-4 final arena, the 0-2 arena (hardest one tbh), and whatever others you can find. The 2-2 explosion boost around the railgun room is also not a glitch, it's like 1-3, the game deloads rooms based around doors opening and closing for optimization reasons and it's deloaded until you open the door (from the wrong side, but hey, lust is a very open layer tbh).

The list of glitches is smaller than you think:

Door Clips: sliding into the level geometry on doors at a slight angle to the left or right of perpendicular to the wall to fall out of bounds. Used notably in 2-3 & 3-1. The clip in 0-1 is similar, however the recent patch made it easier to do, so it's now bordering on intended game mechanic.

Door Checkpoints: loading a checkpoint in close proximity to doors can put the player out of bounds, deload certain floors, and load them in an incorrect place. Was used in 0-2 on patch 1.05, but on the --Early Access-- patch, it is not used in 0-2 due to the end level trigger pipe being given collision; however, the 1st door load is still used to deload the floor. Is used on the current patch in certain 3-1 strats.

Skull Warping: punching a skull key then pausing and loading checkpoint mid punch will let you keep the skull, allowing you to warp it with you to the last used checkpoint. Used notably on 1-1 and 2-4.

Honestly that's it, just 3. If you're planning on doing glitchless runs, please dont limit yourself thinking it's a glitch when it's not.