[section=Basics]
Sentry is an ability you can purchase from Opher. When you use it, Ori summons a butterfly which attacks nearby enemies a bunch of times before despawning. The act of summoning the Sentry causes Ori to hop lightly into the air.
It turns out you can perform other actions during the Sentry summon, or summon a Sentry during other actions. Using Sentry in combination with an up-attack from the sword (Spirit Edge) or hammer (Spirit Smash) can cause Ori to fly into the air at a high rate of speed. This is called a "sentry jump".
[section=Ground sentry jumps (sword)]
Hold up, then press both Sentry and sword on the same frame for a max height of about 25.5 units. Pressing Sentry and then pressing sword on the next frame also works, but gets a tiny bit less height.
Technique: Any method of pressing two things at the same time works. Most people just use two fingers (or one!) to press both keys or controller buttons simultaneously.
Failure cases: When practicing, you'll probably achieve max height at least once pretty quickly. After that, it'll be obvious what it looks like when you make a mistake.
[section=Air sentry jumps (sword)]
Hold up, press Sentry, then press sword exactly 3 frames (0.05 seconds) later for a max height of about 18 units.
Keyboard technique: On keyboard, a lot of players do inputs like this by using adjacent keys (for example, K and L) and quickly drumming their fingers in a rhythm. The rhythm will take practice to get consistent.
Controller technique: Many runners choose to assign Sentry to X and sword to Y (or vice versa), then quickly slide their thumb across the two buttons. The timing of the thumb slide will take practice to get consistent.
Failure cases: If Ori rises by at least a couple units (1 unit = 1 Ori height), it means you were one frame late. If Ori barely rises at all, it either means you were late by more than a frame, or you were too fast (which can become common once you learn to hit the 3-frame timing).
[section=Ground sentry jumps (hammer)]
Hold up, press hammer, then press Sentry anywhere from 21-24 frames (0.35-0.40 seconds) later for a height of about 26-27 units. The optimal timing is to Sentry exactly 23 frames after pressing hammer.
Technique: After you press hammer, Ori will perform a windup followed by a huge swing of the hammer. The optimal timing to press Sentry is while the hammer is still, immediately before Ori begins swinging.
Failure cases: If Ori rises about the same height as a normal hammer up-attack, it means you were too early. If Ori rises more than that, but not as high as a sword sentry jump, it means you were too late.
[section=Air sentry jumps (hammer)]
Hold up, press hammer, then press Sentry anywhere from 16-19 frames (0.27-0.32 seconds) later for a height of about 12-13.5 units. The optimal timing is to Sentry exactly 18 frames after pressing hammer.
Technique: Just like on the ground, Ori will perform a windup followed by a huge swing. The optimal timing to press Sentry is while the hammer is still, the instant before Ori begins swinging.
Failure cases: Most failures look pretty similar because these don't get a lot of height in the first place. Again, just like on the ground, if you rise a little bit more than a normal hammer up-attack, you were probably too late. Otherwise, you were probably too early.
[section=Data and Gathering Method]
All numbers in this guide were taken from OriWotWManager (https://github.com/ShootMe/LiveSplit.OriWotW/releases). I ran the game at 60 FPS using VSync on a 60 Hz monitor, then used the debug menu to set a timescale of 0.1. Controller macros were created in reWASD (https://rewasd.com/) to test various input timings. When testing air sentry jumps, I controlled for jump height by including a fixed amount of jump time in each macro (4 seconds).
Ground sentry jump (sword) data: [pressing Sentry at 0f] sword @ -1f => (steep dropoff) sword @ 0f => ~25.7 units sword @ 1f => ~25.5 units sword @ 2f => (steep dropoff)
Air sentry jump (sword) data: [pressing Sentry at 0f] sword @ 2f => (steep dropoff) sword @ 3f => ~17.8 units sword @ 4f => (steep dropoff)
Ground sentry jump (hammer) data: [pressing hammer at 0f] Sentry @ 20f => (steep dropoff) Sentry @ 21f => ~26.0 units Sentry @ 22f => ~27.0 units Sentry @ 23f => ~27.2 units Sentry @ 24f => ~26.4 units Sentry @ 25f => ~24.2 units Sentry @ 26f => (gradual decline)
Air sentry jump (hammer) data: [pressing hammer at 0] Sentry @ 15f => (steep dropoff) Sentry @ 16f => ~12.1 units Sentry @ 17f => ~13.5 units Sentry @ 18f => ~13.6 units Sentry @ 19f => ~12.5 units Sentry @ 20f => (gradual decline)
