oh nice! I found screens in a bunch more games using the Up, Down, Up, Left, Right, Left, B code:
Spoiler: click to toggle
Magic Jony
Director: Jony
Art Design: Jony
Programmer: Nono
Fishing Challenge/Atlantic Fishing Tournament 2009(?, year seems to be hacked)
Director: Wofire
Art Design: WX
Programmer: Tony
Circle Racing
Director: Wofire
Art Design: Jony
Programmer: Lone Wolf
Zoom
Director: Wofire
Art Design: Jony
Programmer: Liu Wenke
Frantic Fishing
Director: Wofire
Art Design: Jony
Programmer: Angell
Sky Dreamer
Director: Wofire
Art Design: Jony
Programmer: Angell
Colliding
Director: Wofire
Art Design: Jony
Programmer: Sting
Danger Bridge
Director: Wofire
Art Design: Jony
Programmer: Jack Liu
edit- one more:
Masked Man III (Spiderman 3)
Director: Wofire
Art Design: Spark
Programmer: Jack Liu
Generally it seems like older games, newer games, Intellivision-port-hacks and VT03 games don't have them though, at least using the known codes.