Console Box game info help

[autoboy250]

I have a master system 2 sonic built in boxed console. On the box printed by sega as part of the box it says '2 games included'. Obviously one will be sonic. Can anyone tell me what the other game would be please? There's no hints on the box of what it could be.

[Batman666]

I thought of Snail Maze at first, but if it's an SMS2 with Sonic, I don't believe it has that hidden game.

Could be a pack-in game, those were often not in the box as there were no space. Like this for example: