Tricks

Pipe Glitch

If down and jump are pressed on the exact same frame over a pipe, Yoshi both jumps and goes down the pipe. On most pipes, this saves just under 30 frames by speeding up the time it takes yoshi to exit the screen since it skips the animation where he climbs into the pipe. However, on a few pipes in the game, this trick might cause a 1-1 warp. It may also cause a warp to adjacent rooms, as in the second pipe in 2-1 or 2-8. See Warps Info.

Video (Pipe Glitch): https://www.youtube.com/watch?v=loBG8J_wCL4

In this video, the three animations of pipe jumps are displayed:

• The first is simply pressing down + B at the same time
• The second is down + B + Y
• And the last is down + B + A

Gatehack

There are many one-way gates in Yoshi's Island that can actually be opened backwards by several methods. By far the easiest real-time method for opening a gate from behind is to throw a straight upward-aimed egg at just the right spot towards the top of the gate. The egg glitches into the gate, and knocks it open, thus allowing Yoshi to go through an otherwise closed gate. This is used to save time in 2-4 any%, skipping the staircase that is typically used in that area.

Video (Gate Hack): https://www.youtube.com/watch?v=CASHk32QBYs

Gatehack tips:

1. Tap A once quickly to fire the egg -- don't hold A down for a bit and then release. 
2. Hold up the entire time, even after tapping A, as this changes the egg's trajectory to make it more favorable.
3. Hold B (jump) the entire time, and if you miss the first shot let Yoshi autoflutter and try again during the flutter. It is actually easier (bigger frame window) to get the fluttering gatehack than the regular one.
4. Run into the gate from the side. This greatly increases the window of success (~9 frames vs 3 frames) because running into the gate knocks it inwards a little bit, and while it is knocked in it is much easier to get the gatehack.

Another gatehack is used in 6-7 where you carry over the momentum of a Spiked Fun Guy (or its pot) by tonguing it while it travels left, spit it out while pushing towards the gate, the negative x-velocity of the enemy opens the gate for you.

However this trick requires the gate to be spawned with the correct camera position.

This trick works with anything that bounces off the gate (Melon Bugs unconfirmed).

Piranha Skip

After shooting an egg or spitting an enemy onto a Green Piranha Plant, it is possible to travel through them for 32 frames (about half a second) without taking a hit.

Gif (Piranha Skip):

It is also possible to damage boost through these Piranha Plants by facing backwards and running/fluttering into them. Some might find this more consistant than the egg shooting method, however this method is slower.

Piranha skips are commonly used and recommended to practice for the stages 3-8, 4-3, 4-6, 5-1 and 5-7.

Ghost Skip

Normally Caged Ghosts take atleast 4 egg shots to jump over, however when Ghosts spawn they grow from min-max size, shooting them during the growing phase causes them to stop growing and reduce by 1 size. This can be abused to save both eggs and time. There are 2 of these in 3-8

Gif (Ghost Skip): File:3 8 ghost skip

Another skip is used in 6-E where you spit the first Mace Guy into the vertical Caged Ghost. Using visual cues can significantly increase consistency.

Screen Scrolling

Generally, the screen scrolls depending on where Yoshi is heading. 

• Holding down/up may scroll the screen vertically if the level allows for it. Not possible while egg-aiming.
• Jumping may correct a wierd screen scroll vertically.
• Jumping as the screen is scrolling, will scroll it even higher compared to just holding up.
• A Perfect Jump may avoid screen scroll vertically.

Gif (1-7 Coin Sky Shots): 1_7_skyshots.gif

Enemies, collectables and event triggers only spawn when the screen is scrolled properly. This is abused many times in speedruns as for examples the 6-5 autoscroller-skip, spawning red coins for 1-7 beanstalk skip and a flower for 1-2 helicopter skip.

Sprite Overload

You cannot load more than 24(?) sprites on the screen at once. Keep in mind that some sprite slots are reserved for important stuff such as Baby Mario, Toadies etc.

For speedrunning, this mechanic has both pros and cons.

This can be abused to despawn for example: Enemies, Save Rings and Gates to save time. Most noteable is the Bullet Bill Launcher despawn in '2-7.

Gif (Sprite Overload in 2-7):

This can be frustrating for 100% speedruns as it can despawn Fly Guys carrying Red Coins/Star Clouds, which will never respawn even though you go back to reload them.

Red Coin Duplication

It is possible to duplicate Red Coins carried by PATROLLING Fly Guys. You do this by tounguing the Fly Guy, not picking up the Red Coin, going off-screen and spitting it out without killing it and going back to respawn the Fly Guy.

It's possible, but incredible hard to dupe 3 Red Coins (4 in total) from the same Fly Guy, but for RTA duping more than 2 coins is unviable, since the timing for a triple dupe is very tight (close to frame-perfect), but it has been done.

Video (5-1 Triple Dupe): https://www.youtube.com/watch?v=UwLrdA2pJZY
Video (5-4 Triple Dupe): https://www.youtube.com/watch?v=aCDFfw2XK_I

This is commonly used in:

• 2-2
• 2-5
• 2-7
• 4-5
• 4-6
• 5-1
• 5-4

Chicken Baxter

///NEEDS OVERHAUL///
Somehow include some stuff from here: http://yoshispeedruns.wikia.com/wiki/4-7_Chicken_Baxter
Video (Sprite IDs): https://www.youtube.com/watch?v=SKKubUnL-zs
Video (Chicken Baxter Tutorial): https://www.youtube.com/watch?v=ArLYY5gS-MM