There really is no way to go wrong with a game as fun as Sonic CD, truly one of the finest games in the series
GRAPHICS:
The graphics style is pretty much the same as the Genesis titles, but being originaly CD based, it has always had smoother textures and great animation. Here, it is even better, as the sprites are now HD, and look fantastic. There were also some FMVs, which were the novelty of the Sega CD, and they were also up-ed a bit, and look alright, but since they are silly by nature, the simplistic style matches. 5/5
SOUND:
This game has a curious case with its soundtrack. There are two versions of it, a japanese one and an american one. Among the best features of this port is the ability to chose either soundtrack at your leisure, so it can suit the taste of any player. Really, I myself preffer the japanese one, truly one of the best Sonic soundtracks ever. Everything is catchy and just apropriate enough. The american one is good too, but can be a bit too dark, as weird as it sound. Still, one player can change if they so want. Sound effects are still well done, and the few bits of voice acting are a nice touch. 5/5
GAMEPLAY:
This game is a 2D plataformer. You control Sonic, as he runs through six stages, until he reaches the final zone and defeates Eggman once again.
The premise is nothing new, the same thing as Sonic 1 and 2, but this game introduces a few things in the mix. First of all is the introduction of two new characters: Amy Rose and Metal Sonic. Amy is pretty tolerable in this game, and doesn't make much of an impact, and Metal Sonic is a pretty cool villain, and his boss battle is fun and different, so that is good.
Besides these characters, there is also a huge new gameplay mechanic in this game: time travel. As you run through the stages, you can see sign posts that say "future" or "past", and after passing the post and running very fast for a short period of time, you travel in time. This not only extends the replay value a lot, in the sense of seeing all the different variations of the levels, but also is a concept necessary to get the good ending of the game. You have to go in the past of all zones and destroy a generator. After doing that, you create a good future for the zone. If you don't like that kind of hunting, you can go in special stages to get the Time Stones (not Chaos Emeralds), and getting all seven ensures the good future. What is the diference between the good and bad future? Well, on the regular levels it has a difference in the landscapes, which is always nice, and it changes the ending a bit. Really, it is a completionist task, but a cool one nonetheless.
The gameplay itself is pretty much unchanged from the previous games. Sonic runs fast and can jump on enemies. The only addition in this game is a new move, the Super Peel-out, which is like the Spin Dash, only performed by holding up on the control pad insted of down, and Sonic just zooms out. It is a cool addition, preferable to the Spin Dash to get speed since you have to charge the SD before using it in this game. The level design pretty much dictates how good the game will be, and thankfully, Sonic CD delivers it. The levels feel like enhanced versions of previous levels, with more gimmicks such as springs. It can be annoying at times, specially at the hair pullying Wacky Workbench, but it works overall, never being too cheap or annyoing. And since there are 3 variations of every act, there is a lot to be seen. Bosses are also well designed, never feeling like a rehash from a previous one and normally bringing sometinhg new to the table, even if a few of them are a bit too easy.
So Sonic CD has solid, if not a bit over the top, level design, cool time travel gimmics and well done bosses. Really, it feels like a complete package. The only complains I could raise is that at times levels get all over the place, and the dificulty is reasonably low, but even then, it still is a blast to play.
5/5
OVERALL:
Sonic CD is a fantastic 2D plataformer, and a landmark on the series that once was on top of its league. While some will dislike the level design, it is good overall, and the replay value is very high, making it a must buy, specially at a low price point.
The good:
-Nice animations
-Soundtrack is really good, and comes with both versions
-Fixes some bugs and annoyances of the original version
-Level design is creative and fun
-Loads of replay value
The bad:
-At times can be a bit too over the top on the level design
-On the easy side