Double shot - Shoot and then jump immediately after to fire two shots very quickly at the cost of one, conserving a lot of ammo over the course of a run and killing the 2-hit guys quickly.

Ladder/Rope jumping - Pretty self explanatory but climbing a vertical structure with a series of jumps is much faster. It can take some practice but you only need to push a direction for a split second while pressing jump to climb in such a way as to not come away from the structure. thereby simply holding up will regrab, rinse and repeat. Furthermore, if you're jumping to a rope from the left or right aiming to get across to the other side, a frame perfect jump input as you're about to grab will retain speed allowing you to jump much further and faster from it. The TAS uses it everywhere chaining multiple ropes this way. It is rather inconsistent though.

Speedkeep - jumping onto "non standard" ground such as floating ledges, tops of ladders or anything the game deems not the main platform prevents stopping to run again.

Water jumping - Swimming at the surface and jumping out repeatedly is significantly faster.

2-hit roll - If you hit an enemy as the roll comes to a stop you can deal 2x hits, killing strong enemies in one roll. Largely useless where double shot can be used instead and it's very precise but does have a few uses in specific areas, especially when rolling onto a patrolling enemy from above. The first hit deals damage on their head, they turn to walk back towards you and the last few frames of the roll finishes them off.