Contextual graphics, part 4: mind your head

In standalone Sonic 3, if you go to the entrance of Knuckles' route in Marble Garden Zone 2, you'll find that the bottom camera boundary gets locked in anticipation of the cutscene boss encounter. In Sonic 3 & Knuckles, however, this was modified to lock the top boundary as well.

The reason for this becomes evident when you enter the cutscene area in standalone Sonic 3. Yes, the cutscene does work; in fact, the entirety of Knuckles' route all the way up to the boss area works just fine, and interestingly, the object layout is actually slightly different to the one in S3&K. Be sure to check it out!

Anyway, the problem is, when the boss loads its graphics, it overwrites the graphics used by the Relief enemy, causing it to appear as a jumbled mess if it scrolls into view. In order to quickly work around this, the developers made it so the top camera boundary locks along with the bottom one for this cutscene only.

What's interesting is how they handle releasing the camera lock. If you hold up the entire time, you'll realize the camera remains locked for a seemingly arbitrary duration after the cutscene has already ended. Well, the problem was showing the Relief while its graphics aren't loaded, right?

So in this case, the game waits for the Nemesis decompression queue to be empty before releasing the camera. Once the queue is empty, the Relief's graphics are definitely done loading, which means it's safe to scroll it back into view.