Object and ring layouts could have been reused, but owing to their nature as an ordered list, and to the fact that they're streamed directly from ROM, makes them unamenable to being patched, and the developers needed to patch them for quite a few different reasons.
The first reason is difficulty tuning. Most people immediately remember the spring at the start of Hydrocity Zone 2 being changed to an extra life, but it goes beyond that, with the addition and removal of rings, spikes and enemies at various points in each level.
Launch Base Zone in particular was drastically toned down by removing many of the Orbinaut enemies. After all, it's no longer the final stage of the game.
Another reason is fixing bugs. For instance, in Sonic 3, it's impossible to reach the highest route through Icecap Zone 2 when playing as Sonic. Sonic 3 & Knuckles fixes this by adding an extra trampoline early on in the stage.
In Marble Garden Zone 2, a lot of extra objects were added to the area where Sonic and Tails' path splits off. The most important being the GTGT collision block, which prevents Knuckles from climbing the wall and hitting the Relief's eye.
Most important however, are Knuckles' paths. In Sonic 3, they are in myriad states of completion, ranging from missing star posts, to being completely devoid of objects, as is the case of Carnival Night Zone 2.
It's not uncommon to also see refinements to the existing object placement, such as the spikes in Angel Island Zone 2, which were probably moved up to prevent players from just walking into them.
Reader Silver Sonic 1992 asked:
Wait, so how was Sega able to use Sonic 3 objects in Sonic 3 & knuckles?Since object code can't be reused from the lock-on cartridge, all Sonic 3 objects are programmed directly into the Sonic & Knuckles ROM. Rather fortunately, this creates another opportunity to introduce bug fixes, as well as add specialized behavior for dealing with Knuckles.
Is it possible to see a full visual list of layout changes?
ReplyDeleteHey! What a great site this is. I too would very much like to see some kind of list of all the changes. Also, I wonder if the author could explain some of the odd ring placement in S3K - rings inside walls, as in SOZ, the one ring that's outside the last loop in Sonic's AIZ2, double rings and things like that.
ReplyDeleteSorry for taking so long getting back to this.
DeleteI'm not sure I could explain those oversights any better than saying they're oversights -- who knows how they got that way? I could make a post sometime pointing out the most egregious ones, though.
I realize that full documentation of all the layout changes between Sonic 3 and Sonic & Knuckles would be a great asset, but it would require also a tremendous amount of work, and I'm not sure how I could make it fit into the blog format. We'll see.