Submission #4514: Aglar, marzojr's Genesis Sonic 3 & Knuckles in 26:53.06

Sega Genesis
Gens 11 svn351
Sonic and Knuckles & Sonic 3 (W) [!].bin
Submitted by marzojr on 12/9/2014 10:31:40 PM
Submission Comments
Started at the same time as the Tails run, and worked on at the same time as its twin run, this run has been years in the making. Like the Tails run, a disassembly of the game was used in order to squeeze the most of every trick. This run saves 03:00.45 in real time over its predecessor, 02:43.81 of which is saved in in-game time. Every single level has been improved from the previous run, and none of Nitsuja's or Upthorn's input survived.
Note that the rerecord count is an estimate.
Emulator used: Gens 11 svn 351 + S3KCamhack + SolidityViewer + (partial)HitboxDisplay + LUA HUD for Genesis Sonic games

Game objectives

  • Ignores delays caused by bonus effects
  • Aims for fastest (primarily in-game) time
  • Takes Damage to save time
  • Abuses death
  • Abuses programming errors
  • Counts time spent dying
  • Manipulates luck
  • Has one speed/entertainment trade-off.


General Comments

Note: Comments by Marzo.
This run was made with constant reference to the disassembly available at Sonic Retro. This disassembly was used to determine the exact positions where the camera locks, how bosses and badniks behave, how several glitches work, and so forth. All this information is being collected and revised, and will be released in the future.

In-Game Time Table

Angel Island 10:35::550:38::45-170
Angel Island 21:14::531:16::23-90
Hydrocity 10:18::370:30::26-709
Hydrocity 20:21::580:23::37-99
Marble Garden 10:50::560:29::291287
Marble Garden 20:03::240:35::36-1932
Carnival Night 10:32::280:34::50-142
Carnival Night 20:40::220:41::41-79
IceCap 10:59::061:00::14-68
IceCap 20:00::430:00::44-1
Launch Base 10:27::520:31::55-243
Launch Base 20:25::500:26::26-36
Mushroom Hill 10:32::270:32::50-23
Mushroom Hill 20:32::500:34::05-75
Flying Battery 10:42::490:56::16-807
Flying Battery 21:06::131:11::21-308
Sandopolis 11:10::131:39::16-1743
Sandopolis 20:57::191:09::47-748
Lava Reef 10:48::481:03::23-875
Lava Reef 20:20::530:21::40-47
Hidden Palace0:16::360:17::27-51
Sky Sanctuary0:52::130:52::25-12
Death Egg 10:57::281:04::03-395
Death Egg 21:37::152:18::06-2451

In-game time lost to deaths

Hydrocity 20:05::210:05::210


Launch Base 20:29::360:29::351
[1] The value after the final colon pair indicates the in-game frame counter, and is restricted to the 0-59 range. It is updated every frame (except during lag frames), and increments the in-game second when resetting to zero.

Level-by-Levels comments

Here we mostly only mention what's not obviously clear when watching the run, each other situation pretty much speaks for itself or has been used in earlier TASes of this game.

Angel Island 1

I had already improved the start a lot; Aglar went in and took it even further. It is possible to perform the loop zip on the second loop too, it is useless without a lightning shield; Knuckles or Hyper Sonic can also make it. Delaying a bit after the scenery burns down lets me bounce off the spring on the top and lets me carry on more speed

Angel Island 2

Improved precision and a different route to the switch.

Hydrocity 1

A 2-player variation of the stair clip is used here, which in this case was much harder to execute as the object that stops the horizontal movement resides quite far from the edge of the terrain. The quick death for the next act was setup at no cost thanks to Tails.

Hydrocity 2

Better camera management for the level wrap, plus a new way of getting into the boss arena that allows a frame-perfect kill.

Marble Garden

Tails moves as in the Tails run, carries Sonic along. When landing, Tails touches down 1 frame before Sonic, so the flight timer is not set and allows Tails to pickup Sonic right away later. First lightning shield is skipped, the second one is picked up with no cost in time. Improved precision carries the rest, with a surprise twist: Nineko's trick with solo Sonic or Knuckles of doing both acts at once can actually be done as Sonic + Tails. The condition for it to work is that Tails must be off-screen at one specific frame; this is not normally possible if you don't know the condition, which was figured out through the disassembly. The pattern at score tally minimizes the number of lag frames.
By the way, I was a bit sad about finding this trick: it is possible to use the route from the Tails TAS in act 2 and hit the boss above the ceiling; Sonic and Tails can deliver all 8 hits this way, but it ends up being a lot slower.

Carnival Night 1

Scrolling a barrel and a set of spikes off-screen, then being dropped through them by Tails leads to a faster level wrap. Entering the wall at the boss allows zipping out at at the right time, allowing for a nearly frame-perfect kill -- it is theoretically possible to beat the boss 4 frames faster, but Sonic simply can't move fast enough for it. The original version of the ground entrance was by DMTM and used a bubble shield; I proved it was possible to do it without the shield.

Carnival Night 2

Zip from the start, better precision and better camera management.


Better precision all the way. 43 frames of "act 2" after the boss are now accounted; previous runs did not count this time, which made them 44 frames shorter in in-game time than they actually were.

Launch Base 1

Based on the Tails trick and on the Mushroom Hill 1 door, this trick is almost as old as the version with Tails. Better boss fight, together with extra setup for death right after signpost stops, allows skipping the score tally entirely.

Launch Base 2

Better boss fight from lodging Sonic inside the pipe. Unfortunately, it is not possible to speed up the transition, and it got longer by 1 frame.
Warning: If you watch this level with a camera hack, be sure to get the latest version of the S3KCamhack in the thread, or Gens will hang.

Mushroom Hill 1

It is theoretically possible to use Tails to enter terrain right at the start of the level, before the Knuckles cut-scene, and level wrap right away; but this does not work, and Sonic is teleported back to watch the cut-scene. And while he will still be on terrain and be able to zip right away, it ends up being slower overall. Anyway: improved ground entrance.
Warning: If you watch this level with a camera hack, be sure to get the latest version of the S3KCamhack in the thread, or Gens will hang.

Mushroom Hill 2

Improved precision, better management of Tails.

Flying Battery 1

Tee-N-Tee's new zip for Tails can be used here, but it is slightly slower than this.

Flying Battery 2

Used the boss of the previous act to gain slope glitch, and bounced the signpost to obtain a lightning shield. The latter is crucial for this route, as Tails cannot follow Sonic on this route: CPU Tails despawns when off-screen with slope glitch. The speed of climbing at the end is irrelevant as long as you don't die.

Sandopolis 1

Yes, as it turns out, this zip is possible for Sonic -- it requires entering it at perfect pixel position with near zero speed. I had previously tried only with positions attainable within the wall (trying all subpixels), and thought it was impossible; Aglar proved me wrong. The needed flame shield was nabbed after the boss, and used to setup object positions on next act.

Sandopolis 2

Several new ground entrances, and improved precision throughout. One frame is wasted between two hits on the boss to save 30 from glitching his invulnerability counter.

Lava Reef 1

The Tails route can't be followed by Sonic, so we had to improvise a bit. The two characters can then team up to descend faster and setup a zip left, which locks the screen further left for the cut-scene. The idea of going through the drill came about by watching Amy do it in WST's TAS.

Lava Reef 2

Level wrap is now perfect: using spindashes to keep camera as far right as possible while zipping left, then using a flame dash to nullify the camera lock right after the level wrap.

Hidden Palace

Improved precision up to the teleporter. It is possible to gain 1 frame more up to it, but the teleporter is the one object in S3&K that has a 4-frame frame-rule. Glitched the boss even more, so Knuckles is down before his music starts... and then broke the level.

Sky Sanctuary

Replayed the level entirely, and managed to gain 3 cycles of the teleporter's 4-frame frame-rule.

Death Egg 1

9 frames were gained in the first frame of input in the level. The Tails zip at the start seems impossible; so improved precision and a couple new zips carried the day. Ditched the lightning shield for invulnerability frames, in order to get a frame-perfect kill at the boss. Used Orkal's trick to break the level transition and die with the timer stopped.

Death Egg 2

Level wrap by gamble5688, with lightning shield by DMTM.

Other comments

Thanks goes to Nitsuja and Upthorn for their Sonic runs;
to Orkal for his glitch videos;
to HHS for his explanation of the Angel Island/Hydrocity transition glitches;
to mike89 for his blooper videos;
to HDL for his general awesomeness at this game;
to the folks at SonicRetro involved in the making of the S3&K disassembly.

Potential improvements

There is a small pause at the end of Sky Sanctuary to manipulate Red Eye; if he were to be replayed, as well Death Ball in act 2, this pause could be removed to save 3 frames.

feos: Accepting as a (notable) improvement over the existing run. To whoever would publish it: this run would need a camhacked copy of each encode (WFIW).
Spikestuff: ...SEGA...
Last Edited by on 1/1/2022 6:13 PM
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