Sonic Labyrinth is a puzzle and platform game featuring isometric game play. Sonic must obtain keys located throughout the first three acts of each zone and then battle a boss to retrieve the chaos emeralds. While Sonic has an incredibly slow walking speed, there is plenty of super fast bouncing around that makes good use of the spindash. The best ending requires entering the bonus stage in 2-3 and requires completing Stage 4-2 with 2'00 or more remaining on the timer.
Movie Features
- Emulator Used: Bizhawk version 1.11.9.1
- Aims for fastest time
- Achieves the best ending
Spindash and Rolling
- The spindash can launch Sonic at one of four different speeds. This is determined by the duration of time that the spindash is charged.
Spindash Speed
Charge
(frames) | Speed
(sp/f) | Speed
(pixels/frame) |
|---|
| 1-15 | 512 | 2 |
| 16-31 | 768 | 3 |
| 32-47 | 1024 | 4 |
| 48-63 | 1280 | 5 |
This game uses 256 subpixels per pixel
- While rolling out of a spindash, Sonic can accelerate for a period of time that is twice as long as the length of time that the spindash is charged, capped at 126 frames. Acceleration during this period is 15 sp/f2.
- When the rolling acceleration period has ended, speed loss can be limited to 1 sp/f2 by depressing the direction buttons in the same direction Sonic is moving.
- Speed loss while rolling with no buttons depressed is 16 sp/f2. Braking while rolling reduces speed at 31 sp/f2.
- The optimal time to spend charging a spindash generally depends on the distance needed to travel, the need to change direction while rolling, and the amount of lag generated from charging a spindash. The table below shows which length of time is optimal for travelling in a straight line and without accounting for lag.
Time Elapsed
[charging+rolling]
(frames) | Charging
Time
(frames) | Initial
Speed
(sp/f) | Maximum
Rolling
Speed(sp/f) |
|---|
| 1-19 | 1 | 512 | 542 |
| 20-23 | 2 | 512 | 572 |
| 24-27 | 3 | 512 | 602 |
| 28-31 | 4 | 512 | 632 |
| 32-35 | 5 | 512 | 662 |
| 36-37 | 6 | 512 | 692 |
| 38-86 | 16 | 768 | 1248 |
| 87 | 17 | 768 | 1278 |
| 88-140 | 32 | 1024 | 1984 |
| 141-226 | 48 | 1280 | 2720 |
| 227-230 | 49 | 1280 | 2750 |
| 231-235 | 50 | 1280 | 2780 |
| ... | ... | ... | ... |
| 282+ | 63 | 1280 | 3170 |
Table is truncated for charge times between 50 frames and 63 frames. Time spent rolling was used instead of distance as an approximation for distance needed to travel and corresponds to the charging time used in the same row.
An example for how this is useful: A 6-frame charge can cover a distance of 20944 subpixels in 37 frames. A 16-frame charge could only cover 20691 subpixels in 37 frames.
General Movement
- The game tracks position with a Cartesian coordinate system where one axis defines height and the other two axes are aligned diagonally, relative to the screen. Ignoring the height axis, walking or releasing a spindash horizontally or vertically relative to the screen will give Sonic full speed along each axis with a velocity that is the sum of those two vectors.
- Walking speed is 128 sp/f.
- Slopes will accelerate Sonic downward on the slope and are too steep for Sonic to walk up.
- When Sonic rolls off an edge, speed and direction are fixed until Sonic lands. While falling, walls do not alter any of the speed values. The wall will stop motion along one axis but Sonic will continue to move along the other axis. When the wall is no longer in the way, Sonic will resume moving along both axes at the initial speed.
- Falling acceleration is 48 sp/f2.
- The game divides surfaces into rectangular areas. When Sonic is falling across a transition from one of these areas to another, falling speed is reset to zero.
- Some objects will bounce Sonic, such as bumpers and flippers. These launch Sonic at a fixed speed, depending on direction, regardless of the speed Sonic had when interacting with the object.
Power-ups (Unused)
Power-ups appear as sets of triangles with various colors that change frequently. When collected, Sonic will pause momentarily, which is time consuming and typically not useful
- Blue - Walking speed is doubled
- Green - Destroys all onscreen enemies
- Pink - Awards an extra life
- Red - Gives Sonic invincibility
- Yellow - Adds 30 seconds to the timer
Score Tally
- The score tally appears after completing a level. Points are awarded for speed, which is based on time remaining, and rings collected.
- The time left when completing a level is converted to a speed at a rate of 5 km/h for every second left and is capped at 900 km/h (3 minutes remaining).
- Enemies add 5 seconds to the timer when destroyed, resulting in a loss of 10 frames in most cases. Keys add 30 seconds when collected.
- The score tally increments the score at a rate of 100 points every 2 frames until the remaining score to add is less than 100. Then it increments the remaining score at a rate of 10 points every 2 frames. This makes finishing levels in the last 7 frames of an even time slower than finishing the first frame of an odd time because waiting for the even time increments the tens value of the speed bonus (adding 2 frames) but also sets the ones value to 0 (subtracting 10 frames).
- Rings only count toward the score on boss levels and are worth 10 points per ring.
Lag
- This game has a lot of lag.
- The game has a few different types of lag. One type still has the game complete the calculations for that frame and successfully render, but it does not read input, rather it just copies the input from the previous frame.
- Sonic tends to generate lag when moving.
- Changes in earlier levels generally cause later levels to change, particularly when there are changes in the lag that copies the controller input from the previous frame.
Zone 1-1 Labyrinth of the Sky
One enemy holds a key and must be destroyed to collect the key. Avoiding the other 2 enemies that were destroyed would have been slower overall. The zone features conveyor belts, bumpers, and ice. Ice has the effect of giving Sonic an increased speed but only while Sonic is travelling across the ice.
Zone 1-2
This zone starts off with a 63-frame charge spindash which was very useful to steer the rolling direction up the ramp to avoid corners while preserving speed as much as possible. A few corners were barely avoided after the second key at the cost of some speed but this was still faster than bouncing on additional walls. The third key is collected while in the air so the animation for collecting all keys is skipped.
Zone 1-3
The first spindash uses 56 frames to charge and collects 2 keys while ahead of the camera, one in the top corner, and the second in a corner near the bottom of the map.
Zone 1-4
Rings cost time during the score tally and collecting them tends to generate lag so they are avoided. Some movement during the ramp segments of the game tend to create additional lag, which is also avoided. Lag generated before the boss fight does not delay the boss spawn. The boss takes 10 hits to destroy. The objects that detach from the boss are invulnerable and cause Sonic to bounce away while rolling. This rebound was abused at one point where Sonic would bounce off one of these every frame and set up getting the next hit on the boss without any delay.
Zone 2-1 Labyrinth of the Sea
This level features cannons. Some cannons alternate the direction they aim. Those cannons start at the same point in their cycle when loaded. They load when the camera is close enough and unload when the camera moves too far away, which makes it important to approach them in a way that the desired direction can be used as soon as possible. The approach to the cannons after collecting the second key made the most use out of this. A slower approach to the cannon forced the camera further left which allowed Sonic to get to the cannon while it was aiming toward the last key.
Zone 2-2
This zone features several doors which creates a maze. Additionally, some of the doors do not return Sonic to the same door that was entered to get there. The first enemy destroyed drops a key that is not retrieved until later. Keys that are dropped from enemies, or dropped from Sonic, will remain on the ground for a short period of time before returning to their original location. The red liquid in the zone cause the time remaining to drop at a rate of 1 second every 8 frames but only while Sonic is in the liquid and not rolling. The 16 frames required to reduce the speed bonus an increment of 10 km/h does not sufficiently compensate for the 10 frames saved in the score tally.
Zone 2-3
The trip immediately after the first key required a small amount of speed along the up-left axis as several walls make travelling all the way directly down-left not possible. The barrel can launch Sonic to one of two locations. The location used in this run requires the buttons RIGHT, 1, and 2 to be depressed during a check on a particular frame. This gives Sonic access to a switch that unlocks the BONUS area. In this run, the BONUS area is accessed shortly after collecting the last key. Typically, when a key is collected, the time remaining is rapidly incremented 30 seconds. However, when a door is entered, this process is paused until the next room is entered. The next room in this case is the BONUS area, which has its own timer. The remaining amount of time that the key awarded, 20 seconds, gets added to the BONUS area timer. Extra time earned there does not get transferred back to the Zone 2-3 timer which saves 100 frames on the score tally.
Sonic is awarded the emerald simply by entering the BONUS area and is not accompanied with any visual indication that it was collected. The BONUS area does not have an end goal. Rings can be collected with an extra life being awarded for every 4 rings that are collected. Sonic exits the BONUS area when time runs out or Sonic falls off, the latter being much faster.
Zone 2-4
The boss fight starts out with smaller enemies that spawn and attack down an alley, then the boss spawns on the left side of the zone and moves to one of three locations to launch a projectile down the associated alley. The length of time that passes before the boss spawns is influenced by the number of enemies destroyed. The greater the number of enemies destroyed, the earlier the boss spawns. The manipulation for the destination was not determined, however, trial and error showed that the boss moving to the middle alley was the fastest. Additionally, the length of time that the boss will remain vulnerable before moving also varies which was manipulated to be long enough to land all 5 hits during the first cycle.
Zone 3-1 Labyrinth of the Factory
The green sections with horizontal waves in this zone stop Sonic and traversing them is very slow. One exception is that Sonic will not be affected by them when skidding to a stop. This technique was not use for the first key collected as the green area is small and takes only a few spindashes to traverse. The star platform loads when the camera gets close to it. The green teleporters have a fixed location that Sonic is sent to when used.
Zone 3-2
This zone has several camera timed objects so loading them quickly is a significant part of fast completion time. A 48-frame charge is not used for spindashing from those platforms because going faster over the short travel distances does not compensate for the additional lag generated.
Zone 3-3
This zone also contains a key located on the green stopping field. This time, a skid is used to load the next star platform sooner. The second key is just far enough away to force that platform to unload and load again, which makes waiting for it to return unavoidable. The third key has a chance of disappearing after destroying the enemy.
Zone 3-4
One ring was collected during the downhill section to land the first few hits on the boss quickly. This requires occasionally standing inside the boss hitbox which would result in taking damage if Sonic was not already invulnerable from a previous incidence of damage. The fast rolling around that destroyed the enemies as they spawned was a few frames faster than standing still, waiting for the boss to spawn. The boss bounces Sonic away at a speed of 768 sp/f. This makes charging a high speed spindash not useful as the speed would not be conserved. The boss takes 10 hits to destroy.
Zone 4-1 Labyrinth of the Castle
Nothing gets in the way of high speed action.
Zone 4-2
This is another maze with one-way doors. The switch that was depressed removes a barrier that blocked access to the third key.
Zone 4-3
This is the largest maze in the game with 32 doors and 20 unique destinations. There were a lot of reasonable route options to check here.
Zone 4-4
The boss has two phases with each phase taking 10 hits to destroy. The boss spawns off to the left of the zone and homes in on Sonic. After each attack, the boss homes in to the new position of Sonic. For this reason, the boss is manipulated to stay in the left corner to minimize travel time. On each decent, the boss is low enough to take two hits with a few frames of leeway. The amount of lag that various movements from Sonic would generate varied between the two phases which resulted in a different sequence of inputs being used for each phase.
Memory Addresses
Suggested Screenshot: Frame 31401
Memory: The game is supposedly very hard to control but despite that it looks very optimized.
The game has fast paced action, with Sonic frequently bouncing around the field like it's a pinball table, yet still feels well planned like any TAS should. I enjoyed it and so did the rest of the audience.
Accepting to Moons.
