Hello c: I wanted to suggest some games for Let’s Plays with good vocabulary selection, Japanese language compatibility, and simple mechanics that should be accessible to non-gamers.
Loddlenauts - A game about swimming underwater, cleaning up trash, and raising fish pets. Would be good for ocean/fish vocabulary (beach, seaweed, coral), action words for swimming, movement/directions, cleaning vocab, every day object vocab (plastic, oil, TV, garbage bag), and technology vocab. Often on sale for half price.
Seasonspree - A light puzzle game, ~2 hours. Includes a “time traveling” element, when you move to the right time passes and when you move to the left time goes backwards. Easy puzzle game. Vocab for time (days, weeks, hours; before/after, etc), seasons and nature, different animals, action verbs. Short dialogues too.
Sprout Valley - very simple farming game with many different decorative objects and clothes. different islands to travel to. compared to stardew valley it is much simpler, slower, and calmer. There is more time to describe different things and less gameplay. It often goes on sale for $2.
I hope these suggestions might be helpful. c: It seems difficult to find games that are simple enough to be useful to beginning learners, so I wanted to suggest some.