So I recently took all the text from Rabi-Ribi, a cute 2D metroidvania with scalable difficulty and a high skill ceiling, and generated a deck on jpdb with it. The vocabulary is the easiest of any of the games I’ve tried so far. (I’m N4-ish and have 70% coverage of it.) Text is pretty frequent too, as the game is interspersed with dialogue-driven cutscenes.
If you own the game, you can just pass the text files into jpdb and generate a vocab deck from it, or use some other tool with similar capabilities. Aside from Rabi-Ribi, this has actually been a pretty fun process for me, though it helps if you understand regex and how games typically organize their data.
EDIT: I just remembered Final Fantasy Mystic Quest, an SNES game originally intended as a “starter JRPG” for young kids. It’s a slog playing it in English as an adult, but I bet you it’d be entertaining if you played it in Japanese, especially if you emulate it and have 2x speed on a hotkey.