The game - Teddy Boy Blues - Sega Master System | SMS

Once upon a time there was a boy, Teddy Boy, but he was clearly bored. With a pistol in hand, he jumps through the levels, shooting everything that moves in his path. Weakly. But several hacks were made for this game, including one involving Mario :)
I had problems running this game in the Meka emulator. Try Kega Fusion or other emulators.