Simply amazing!
Sonic the hedgehog is the first game to feature Sonic and is available on the Sega Master System and Megadrive (Genesis).
Sonic is one of the most simple games I've played as the controls are as follows, Left on the D-Pad to move left, Right to move right, A, B, or C to jump. It's that easy.
The object of Sonic the Hedgehog is to free animals trapped in robotic enemies and defeat Sonic's arch nemesis, Dr Robotnik.
The are multiple zones which feature 3 stages in each with the 3rd stage being the boss battle. You go through the stages collecting rings and defeating the robots. You can either do this by jumping on to them or spinning in to them. Once you've defeated an enemy, the animal will be released. On the boss battles you face Robotnik in various situations depending on the zone. So if the zone is water oriented, Robotnik will come at you with something to do with water.
There are also bonus stages that you can access if you have a minimum of 50 rings and the end of the first two stages of a zone. Completing the bonus stage gives you Chaos Emeralds and most of the time extra lives or continues.
The graphics in Sonic add a lot to the game. They are nicely detailed and bright and the characters have smooth animations. And the game is almost completely free of slowdown. The only time it does slow down is if you have a lot of rings and get hit by an enemy. This isn't that bad as it seems like a cool slow motion effect.
Sonic the Hedgehog has great music too. Especially the theme for the Green Hill Zone. It's all very catchy stuff and doesn't get annoying. The sound effects are also very good. From jumps to the screeching of Sonic's feet and when you collect the rings, all the sound effects are really clear and suit the game well.
That's pretty much all I can say about Sonic. You really have to play to realise how great it really is. For the people that haven't played it (are you crazy?) you should by a Megadrive and a copy of this game, you won't be dissapointed!
It's the first game I played on the Megadrive and I still find it awesome to this day!