More stuff I found in the game boy leak:
-Hammerin' Harry is a unique US version, this was Europe and Japan only. It has a voice sample that appears to be in english! Other than that it's Hammerin' Harry.
-Space Date is apparently an unreleased european version of Out of Gas
-Unfortunately the YuGiOh games are just Dark Dual Stories, but without the subtitle on the title screen for some reason. Too bad.
-Edd the Duck actually... isn't terrible. It comes from the Sonic school of platforming, no loops but you got speed. Not amazing thanks to the screen real estate.
-Bobby's World was once a Home Alone game: https://tcrf.net/Bobby%27s_World_(Game_Boy
) (Strange, this link goes to a completely different place when I place it in the post)
-ZAS is an european version, but heck if I can tell a difference between that and the Japanese one. This is another game with that "wow" factor when it comes to graphics but for a SHMUP on the DMG.
-There are a few other european games slated to go to the US but never did, like Jimmy White's Cueball or David Beckham's Soccer. I don't think there's much of a difference here since it was already in english.