Even though the Sega Genesis couldn't quite keep up with the Super NES's technical specifications a decent number of games manage to go above and beyond the system's limitations, resulting in some fantastic 16-bit eye candy. Retrogaming has put together a list of Genesis games that pushed the limits of the console. Lots of interesting tech talk here.
According to Vectorman’s head developer, Richard Karpp, A large percentage of the levels implemented a creative use of the Genesis’ scrolling backgrounds For example, it was possible to specify a different scroll offset for each horizontal line, which could give a parallax effect. It was used vertically in a few levels as well, even though vertical scrolling was limited to 8 pixel chunks. Some examples for of its uses were for waterfalls and the conveyor belts.
I can't say I disagree with anything on the list, although there are a few titles listed that I've never heard of, let alone played. Treasure's games continue to get high marks and Konami even gets a word or two in edgewise. No Capcom though? Didn't Street Fighter II: Special Champion Edition push the limits in terms of cartridge memory?