Samurai Shodown is one of the fighting games that you have to have in your collection for Sega Genesis. I loved playing this game with my friends, and I still occassionally play this game against the AI. It's a fighting game where you can choose between 12 unique characters.
The setting is the medieval Japanese society of samurais. You can either choose a character and fight all the other characters controlled by the AI and defeat the final boss. You can also play against your friend.
What this game requires is timing, quick reaction, and presence of mind. You have to be able to understand the advantages of each character and their moves, what to do and what not to do in different situations and against different characters.
Highly recommended. Buy this!