My VLDC13 entry. Music: Kero Blaster - Time Table [ Ссылка ]
Nerd information:
The glitch used in this level is pretty similar to the one used in Hatching Time from UB2. Normally, when Yoshi hatches, Mario freezes along with all other sprites. However, if a Yoshi is sinking in lava and a new Yoshi hatches, and the new Yoshi is in a higher sprite slot than the sinking Yoshi, Mario and certain sprites won't freeze during the hatch. The trick in this level is to have Mario not freeze, but have all other sprites freeze, creating the illusion that time is frozen for everything except for Mario. In reality, it is actually Mario that is behaving in a glitchy way, and all the sprites are behaving normally.
Mario's freeze depends on a few conditions: the initial position of Mario and whether the current level has any horizontal camera hijacks. Several hijacks prevent the glitch from happening: autoscroll, no horizontal scroll, and layer 2 side scrolling sprites. The only way to prevent horizontal scroll while allowing the glitch is to only design on screen 0 (which is why all of the rooms in this level are vertical).
Sprites are a bit more complicated. From what I understand, whether a sprite freezes or not depends on its current position and sprite slot relative to the Yoshis. Any regular sprite in a lower slot than the newly hatched Yoshi will not freeze, as well as any and all extended/bounce sprites. Thus, in order for the setups I designed to work, each sprite would need to spawn after the Yoshis and the countdown, leaving them in a higher slot, so that they still freeze. During the hatch, if both Mario and a sprite don't freeze, Mario will still interact with it, which of course isn't ideal.
Speaking of the countdown, I have Lazy to thank for this idea. What happens here is that, in the single screen rooms, the initial "3" marker is p-switch exanimation. The "2", "1" and "GO" markers are a bowser statue, a flower, and a shell, respectively. Bowser statues and shells are great candidates because they are stationary, single tile sprites. Fire flower is a bit trickier since it wiggles, but by using a "1" indicator that is perfectly symmetrical, it appears stationary. In order for the sprites to spawn properly, each countdown sprite in the single screen rooms must have the same X position, while each countdown sprite in the dragon coin section must have the same Y position, which is done using invisible conveyors. The countdown was a great way of indicating the freeze, but unfortunately it loads even more sprites into the level, complicating the glitch. As more permanent sprites (i.e. shell, springboard, etc.) are loaded, it becomes harder and harder to properly trigger the glitch, as more slots are filled.
