Finally threw together a decent explanation of everything :)
- Abuses programming errors in the game
- Takes damage to save time
- Collects no emeralds
Most noteworthy improvements
- Marble Garden 1 (1:05 -> 0:47)
- Marble Garden 2 (1:45 -> 1:00)
- Ice Cap 1 (1:41 -> 1:28)
- Flying Battery 2 (3:08 -> 2:52)
- Sky Sanctuary (1:53 -> 0:55)
Notes about the game engine
- Spindashes give maximum speed after 6 revs. These can be done in consecutive frames by using a different button for each rev.
- Rolling down slopes is faster than running. In most other situations, running is faster.
- Jumping from slopes drastically affects both speed and height. This can be abused even on slightly uneven floors.
- You normally lose speed after after jumping. The deceleration begins when you release the jump button (or when holding it no longer affects your height), but can be halted if you hit the ceiling.
- Jumping from rolling prevents you from controlling yourself in the air. Using any shield special restores this ability.
Quirks/Glitches
- Jumping at the exact point that a downward slope begins gives you a slight speed boost without having much effect on the jump height.
- With a few exceptions, jumping on the exact frame that you land causes the game to completely ignore the landscape. It's as if you were standing on level ground when you jumped.
- It's possible to hit some ledges (those with sloped edges) in such a way that you land on top of it, but hit the side of it at the same time. The result is an instant speed loss, allowing you to spindash without having to waste time slowing down.
- Spindashing from right next to a monitor puts you back on your feet after going through it.
- If you look all the way down then jump, you go off the top of the screen. On levels that wrap vertically (Marble Garden 1, Ice Cap 1, Sandopolis 2, Sky Sanctuary), the game decides that you're actually below the screen, so it scrolls all the way through the level in an attempt to catch up. Sprite based obstacles are only created when they're close to the screen, so this glitch can be used to pass straight through things such as breakable walls, spikes, etc.
Angel Island 2
[0:05] A bubble bounce from exactly the right spot lets you fall through the crumbling platform before it breaks.
[1:18] Control is regained slightly before the bridge collapses. A bubble bounce speeds up the descent to the next level.
Hydrocity 1
[0:05] Holding down and left at the end of the tunnel causes you to catch the edge of the floor on the way out, so you can jump straight to the conveyors.
[0:24] The ramp doesn't change my direction fast enough, so I end up half in the wall on the way up. I hit the wall, and fall down into another part of it. From there, holding left causes the collision handling to push me to the right at high speed, and straight out of the wall.
[0:43] Delayed killing the boss by about 30 frames. Reason below.
Hydrocity 2
[0:19] The rotating pillar would be in the way if I got there sooner. Finishing the previous act slightly later means I don't have to wait as long here. As a result, I get a slightly faster time for this act.
[0:32] Easily reproducable glitch. You can only land on the floor when falling downwards, which means it's possible to jump up and through blue slides.
[0:56] Another way of falling through slides: Skipping over the collision area.
Marble Garden 1
[0:24] Fear the glitch of screen confusion. It takes a few seconds to activate, but it's worth it.
[0:27] At this point I'm jumping straight through a wall that's supposed to be broken by the spinning top I skipped a moment ago...
[0:28] ...and a set of crushing spikes... and a large mace...
[0:29] ...and a spiked pillar... and a set of spikes attached to the ceiling...
[0:30] ...and the screen finally caught up.
Marble Garden 2
[0:05] Only tails is supposed to go this way :)
[0:33] "You're not supposed to be here!"
[0:45] ...or here.
[0:48] ...or here either. The game reset itself a few times while i was recording this part.
[0:52] Behold! Knuckles' boss!
Ice Cap 1
[0:38] Knuckles' route is faster, so I screen-glitched into (and out of) it.
Launch Base 1
[0:10] The tube things hover slightly. If you land inside them when they're at their lowest point, you glitch back out as soon as they arrive at their destination, meaning you don't have to wait for them to stop spinning.
Mushroom Hill 2
[0:10] It's possible to jump on the very first frame that you regain control. I guess the game takes a moment to notice that you're no longer on the ground. You don't spin during the jump, even after using the shield special, so it'd probably look a bit silly with the Bubble Shield :)
Flying Battery 2
[0:11] Backtracked enough to reset the corkscrew thing, but not enough to reset the door. This means I can skip waiting for the damn thing. This is done repeatedly throughout the level.
[2:11] I guess someone screwed up. They forgot to make this wall solid :)
Sandopolis 2
[0:00] All the messing around after the end of the last act was for here. The moving pillar at the start was in the way, and if I'm going to wait, I might as well do so when the timer isn't running.
[0:07] Normally you'd go round the loop twice and up into a spring to send you downwards. Instead, I used a small jump to get halfway into the slope. Then, similarly to in Hydrocity 1, I ran upwards into the wall and fell downwards.
[0:23] Screen glitch. This time I used it to go up through a door without having to push the switch, using the time waiting for the platform to rise as preparation.
[0:33] Another platform, another door, another screen glitch.
[1:23] Used a ghost to knock me onto the block without breaking it. The extra height, in combination with the two ring boxes, makes it barely possible to reach the platform above at it's lowest point.
[1:38] Shields don't take effect for a moment after collecting them. I used this period to bounce onto the top of the spikes to the right. I lost my rings, retained the shield, and was able to spindash off the spikes to save quite a bit of time.
Lava Reef 1
[0:24] Triggered a switch from above and behind.
[0:31] Got below the drilling machine, then jumped up into it just as the floor collapsed, sending me downwards quickly. Enemies have glitched sprites for a short time afterwards.
Sky Sanctuary
[0:33] Normally when you fall down the hole to the right, the screen stops scrolling, you hit the bottom, and you die. I used the screen glitch to get it to scroll below this point before I jumped down. This makes it possible to skip almost the entire level.
Death Egg 2
[0:34] I think the spikes to the right are graphically the wrong way around or something :)
[2:07] Lost the Lightning Shield so I could beat the next bosses faster.
[2:52] I wait for a moment before finishing off Robotnik. This is because if you get the final hit before he starts moving to the right, he'll just sit there exploding for all eternity.