Ordered by time save and effort (top is easier and save more time than bottom).

Gliding

Spamming jump buttons reset fall speed, gain a lot of time on some levels. Example

Water fast fall

Jumping into water is way faster than falling into it. **

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Water fast raise

Thanks to @Arcree, spamming jump buttons in water is faster.

Speed jump

A single full-height jump is slower than a double-small-jump and both have the same height. (500 millis against 400 millis)

Those two down bellow could be usefull in advanced custom levels, but are useless in normal speedrun.

Shrink ray trigger hitbox

It can be used from above without falling. **

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Spike corner

We can land on the corner of spike, it's really precise and not really usefull. **

** Works with extended spikes of Area 26 too. ** **

Gravity arrow hitbox

Watch this. **

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