I've played some of the Megadrive protos today.

Putty MEGA is Putty Squad, unreleased. I loved the game on PC.

Beethoven 2nd is unreleased.

Flint MEGA is an unreleased Flintstones game (it was released for the SNES). It has more realistic graphics than the other Flintstones game and seems to be based on the movie. It's also more fun.

SR 21/03 is Street Racer. Steph's Cartridge is Psycho Pinball.