* By and large it looks and feels exactly like the original (though the picky guys at Sonic Retro have found a few minor gameplay differences that will largely go unnoticed by mere mortals like me -- perhaps the most critical change is that it takes slightly longer to time warp). It's not exactly an HD remake, but then, does it really need to be? Still, the graphics aren't as pixelated as the original (though there's an option to make them so if you're into that).
* No loading times! I wonder if this is the first time we can actually play Sonic CD without ever having to sit and wait for the game to load something.
* It supports widescreen displays and seems to actually expand the display instead of merely stretching (nothing seems out of proportion).
* The Spin Dash has been modified to work like it does in Sonic 2, though there is an option to use the original Sonic CD behavior. The Sonic 2 spin dash is just better anyway.
* Tails can be unlocked by beating the game. As in Sonic 3, he can fly.
* Both the US and Japanese soundtracks are available, though unfortunately you can't mix and match.
* The game autosaves after every level, and you can just reload your save if you get game over (which basically means starting the level over).
* There are Steam achievements, though apparently you can't get them as Tails (haven't confirmed).
* The game crashes for me upon alt-tab.
Maybe it'll work better for others, though. In any case it's no problem to just quit the game at a level boundary and come back to it since it doesn't take long to start the game back up, and you won't lose any lives, score, etc.Here's perhaps the most important thing to us as a community, though:
The engine was fan-made.
That's right. Some dude a couple years back was working on his own Sonic CD engine and made a demo, and it wound up getting licensed by Sega.
Now if only Sega hadn't pulled that Streets of Rage fangame, I might have to actually like them again.
EDIT: I'm late to the party, it seems -- the Sonic CD remake has been available on one or two other platforms like XBox 360 since last month. Still awesome that it's come out on a system I actually have, though
