I just watched this video by Willie, ArcadeUSA.  Has anyone ever heard of this handheld?  Seems it had different names in different regions (Coleco Sonic in the US and Pocket Gear in Europe).  Looks like a nifty handheld.  All the games can be played either on the integrated 2.4" LCD display or output to a TV via composite video.

Here is the list of games on it:

Game Gear Games

    Columns
    Ecco II: The Tides of Time
    Sonic Drift 2
    Sonic Triple Trouble
    Super Columns

Master System Games

    Alex Kidd in High-Tech World
    Alex Kidd in Miracle World
    Altered Beast
    Assault City
    Astro Warrior
    Aztec Adventure
    Bomber Raid
    Fantasy Zone
    Fantasy Zone: The Maze
    Global Defense
    Kung Fu Kid
    The Ninja
    Penguin Land
    Quartet'
    Snail Maze

https://youtu.be/fbqI0XTAgoY