SEGA GENESIS COLLECTION (Official Website)
With a total of 28 (!) games, Sega released a pretty sweet collection of Genesis games for the PSP and PS2.
You are welcomed by a dynamic intro showing you the whole range of games included. The more you play the more features you get (such as interviews and secret games). This type of extra flavor has been appreciated by many gamers who played other retro game bundles such as Capcom's Classic Collection.
It's easy to switch from one game to another, just press Select, then choose to quit and start the next game from the list.
Except for Kid Chameleon, which is a cheap Super Mario rip off, all games are real classics of which many brought something new and innocative to the world of video games, just like the Genesis itself (first 16-Bit game system). Especially, my personal favorite, Comix Zone.
The collection also offers series of games (Ecco the Dolhpin, Sonic the Hedgehog Phantasy Star and Golden Axe) documenting the developement of the games. Most of them are Jump n' Runs but as different as they could be. Vectorman, a game I didn't know before, offers surprisingly liquid movements considering it's a classic Sega Genesis game.
Almost all other games are RPGs such as Sword of Vermillion. Also included are beat 'em up Virtua Fighter 2 and puzzle game Columns. Many games can be played by two players, which of course is still double the fun. Memory Cards are supported of course.