I was going to state this earlier, but got kicked off the computer.
If we are going to make a Sonic 4, we need to remember how each game was progressively coming closer to 3D in terms of art, concept, and engine, as opposed to the flatness of the original game. Zones became highly detailed with more realistic texturing styles such as embedded chrome and carved wood, each with at least one noticeable 3D element, gameplay-wise. Character sprites should also reflect this, so something similar to the Sonic 3 sprites is pretty much a must. The title screens were pre-rendered, too. I think a good example to take for a Sonic 4 would be linking together Sonic 3K, Chaotix, and Sonic Xtreme, and giving them each a close examination to see what would fit correctly to give it the same feel as the classics, but how to "fill the gap" correctly without going too far, so to speak.
Now that I think of it, something inbetween the Sonic 3K and Sonic Xtreme sprites would work really well - the Xtreme sprites have almost perfect perspective, they're pre-rendered, and they have smoother animation. The only thing wrong with them is that they're too big for a Genesis resolution game, and the perspective isn't exactly the same. It could be almost like Sonic and DKC put together or something. What's also important to remember though, is that Sonic 1, 2, and 3K were Genesis/MegaDrive games, therefore it would only make sense to create a game that felt like a Genesis/Megadrive game - using the original soundset with only few higher quality instruments, if any, limiting the color palette and special effects, etc. are all necessary to do this.
We already know that Retro Sonic XG is supposed to be a continuation of the 16-bit series, but if we're actually going to make a game called "Sonic the Hedgehog 4
", then perhaps we may as well make it feel more like the other 3, and a bit less like something you'd find on Saturn or something.
This post has been edited by PC2: 18 July 2008 - 03:40 PM