You were lucky that the game uses a relatively small number of backgrounds so you could complete it using another stage.
I've got a question regarding backgrounds myself. I'm still working on the various Genesis Sonic games on-and-off, and I sometimes stumble on stages where the background is just too distracting. By that, I mean that the colors and patterns make it difficult to separate the two when watching a static map.
I've been thinking that for maps where this is extremely problematic, I could employ a technique used by gaming magazine back in the days: set the background at 50% brightness before pasting the foreground over it, so as to greatly increase the contrast between the two. I think this a nice compromise that would work well with the funky backgrounds of the Special Stages in Sonic 1 (which I removed because it made the maps illegible). You can see a comparison below.
-Normal background:
-Background at 50% brightness:
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Current projects: Bucky O'Hare (NES), Metal Storm (NES), Clock Tower (SNES), Ristar-The Shooting Star (Gen), Sonic The Hedgehog (Gen), Sonic CD (Sega CD), Mega Man Zero (GBA), Battletoads (NES)