Strider (1990 / Capcom)
Also known as Strider Hiryu in Japan. This is an arcade port of a side scrolling action game by Capcom. Strider is one of those games that you can play over and over. The gameplay is simple, yet challenging and offers you plenty of variety through its level design. You go everywhere from future Russia to the Amazon jungle… a flying battleship to a hidden space base. 
Enemies range from a gigantic robotic ape to a menacing cybernetic hitman… even a troop of Russian military who form together to create “ouroboros”. Then there’s the soundtrack… a dramatic and exotic backdrop to the equally exotic stages. Tons of synthesized horns and bell like sounds take full of advantage of the Genesis‘ sound abilities. Definitely check this one out if you haven’t already.
Sonic The Hedgehog 3 (1994 / Sonic Team)
Although not as iconic as its predecessors I have always considered this game to be the best in the series. Sonic Team took everything that made previous Sonic The Hedgehog games great and amped everything up to 11. The animations, the special stages, the music, the levels… everything is bigger. Sonic 3 has some of the best and most classic videogame tunes.
The levels are massive and cleverly designed with the typical Sonic traps and different paths. Gameplay is fast and interesting… with unique “special stages” ranging from 3D action levels to some sort of electric pinball machine. A thorough adventure that is a must-have on Sega‘s 16 bit darling.
Sonic & Knuckles (1994 / Sonic Team)
Take everything I wrote for Sonic 3 and 
add it on to this… This game continues where Sonic 3 left off. Now you can play as the nemesis from the previous episode, Knuckles on his quest through a whole new game. The game continues on from Sonic 3 so much in fact, that you can actually COMBINE the game cartridges and play both games continuously! 
Using special lock-on cartridges you can stack the 2 games and play a 14 level adventure allowing you collect all the emeralds and then transform not only into “Super” Sonic… but also HYPER Sonic. Further more, the gameplay extends allowing you to also collect the emeralds and transform as Tails and/or Knuckles too. So, if the stand alone game of Sonic & Knuckles isn’t enough you can combine it with Sonic The Hedgehog 3 for a monster of 
a game.
You can even combine it with Sonic the Hedgehog 2 to play through that game using Knuckles The Echidna. A nice bonus.
Decap Attack (1991 / Vic Tokai)
Every now and then you find a “hidden gem” that gets tragically under played… Decap Attack is one of these games. Interestingly enough this game is a conversion of a Japanese anime game for which the license to sell in the US was not obtained. Instead, as fate would have it, we get this strange and unique adventure known as Decap Attack.
The core of the gameplay is platforming whilst slinging your own head to attack enemies. Did I mention you play as a mummy? Yeah. This game is unlike any other game, even to this day. The levels are big and fun and feature challenging boss battles at the end. This game is worth getting if you’re looking for a unique and fun adventure that you will not find anywhere else.
Super Hang On (1989 / Sega AM2)
When talking about classic arcade games, its impossible to skip Yu Suzuki‘s Hang On. It revolutionized how people viewed arcade games allowing you not only be a part of the game via the motorcycle controller but also having beautiful cutting edge graphics (at the time). Well, the Sega Genesis got the hook up with a port of Super Hang On.
As arcade perfect as it got back then, this game faithfully recreated the arcade experience at home using your 3 button control pad. Fast and fluid animation along with its memorable music made this game a good, fun time. Another must have Sega title made by one of the greatest minds in video games.
-Bo