A fun and very nicely presented old school Sonic game.
Some levels have floors that make sound launch high into the air constantly.Some levels will shrink Sonic and make him use his small size to find a way through the level.Sometimes you will need to bounce on balloons to move to where you need to go,and some levels have moving floors that force you to run against them.There's underwater levels that make you search for air bubbles occasionally to stay alive and there's levels that have places where you can be crushed easily.
The boss fights are creative because some boss fights are set up like pinball stages,and other boss fights make Sonic run on a moving belt while doding obsticles and battling Eggman and having to do platforming at the same time.Another boss fight forces you to win a race and I won't say who your opponent will be,but you'll have to avoid them as they come charging at you during the race too.
Each level has 2 forms,one of them is future and the other is either past/present.If you want the good ending for this game,you will have to explore the levels and destroy a device in each level that somehow frees that level from Eggman.And you'll have to travel forward and backwards in time within the levels to find these devices.You can travel forwards or backwards in time by finding special devices and when you run past them,it will allow Sonic to travel through time if he can move very fast for a certain period of time(which isn't as easy as it sounds because some levels make it difficult for Sonic to have space to move quickly).So in a way,this game encourages you to explore.
Your progress gets saved after you defeat a boss,so you won't need to redo tough sections or have to search for the devices in the past and future on every playthrough.
The classic style Sonic gameplay that many people love is still there.The game places enemies and obsticles such as spikes in sneaky postions,so even though you can run through levels quickly,you can't be as careless as in other Sonic games.The levels don't have as much rings as other Sonic games either,because I remember in other Sonic games how I could easily collect hundreds of rings each stage,but in Sonic CD,if you're hit by an enemy/obsticle and lose all your rings,you will have very little chance of collecting more than 100 rings.
I love the artstyle for the levels.You will see plam trees,blue ocean,bright green grass.The carnival levels use bright pink colored sections that lite up signs and balloons and it looks very pretty and I like how in that levels it shows a certain female character following Sonic sometimes and you'll see love hearts around her to show she either has a crush on him or is in love with him and it's very charming.There's also some dramtic story scenes shown in the game too.The space level looks great too because you'll be in some sci fi environment surrounded by space.The factory style levels look a bit boring,but that's how they're supposed to.In the future versions of each level,the levels have a polluted,industrial feel and one minute you can see a level that has beautiful palm trees and is next to beautiful ocean water,and the next you will see it very polluted and industrial.
The music for the levels can create some enjoyable or relaxing atmospheres.I like the music for when you're in the underwater city becausei it's relaxing.The music for the colorful and carnival levels has a nice enjoyable atmosphere.The music for the boss fights is a nice change because it gives a more dangerous feel to them,but I don't like hearing the ''ho ho ho'' sound the Eggman makes during the boss fights.
When you get an extra life you just hear a Japanese voice saying ''yes'' which is kinda of cute,but you won't hear any music for it.
This was one of the first Sonic games to have FMV and at the start of the game you'll be shown story footage in FMV and you'll hear a song which sounds a bit too childish.
People complain this game is short,but if you try to go for the good ending,it might take you a while to get it because it's hard to find the devices that you have to destroy and it can be difficult to build up enough speed to travel through time in some levels.
Overall it's a great Sonic game.