Alright so.. I've been eyeing this thread for a while now trying to formulate what I want to say without coming off as mean but... I've got a few questions to make about this project.
First, what IS that custom color
It's so overly saturated it's really hard to look at, it's like you've removed half of the color's shading and made the highlights literally pure white. If you're trying to replicate how Sonic looks in Lost World, you should take into consideration that 3D models (and therefor, their textures) are a whole different beast than 2D sprites. It may look like Sonic's one flat color but it works due to the engine's lighting, to put it simply. 2D sprites require the shading to look good - and you're removing it.
Secondly, the CSS colors are inconsistent with the actual sprites, plus it looks... wrong. It's unsaturated for some reason and his shoes have a gray soles?
Thirdly, the life icon looks super choppy and pixelated. It's even cut off from the top. At this point it'd look far better to try and replicate lost world's hud all together. Right now it looks incredibly lazy, like you copy pasted the icon and didn't bother to do anything more than that.
Fourthly, the jump/spin sprites are just... a blue ball. With slight wobbling from what I can tell. To be honest it just looks terrible, I don't see the reason to remove the perfectly alright ROLL frames. Are you trying to replicate the jump from SLW? To be frank it's still not pretty there either, it's just a blue ball. You have the sprites, why remove them?
And finally, this is just... a mishmash of lua. That you didn't make. Sure, you say you got permission to use these but honestly? This feels like 90% other people's work and the rest is just you compiling it. I could be wrong, you could have further plans to work on with this project but I implore you to put in some work to polishing this character if you seriously care for it.
Even then, I don't feel this justifies as a separate "character", might as well just make it a Lua modification for vanilla Sonic.