Disclaimer: I'm not affiliated with the makers of this game. I just really like it.
I have my Steam language set to Japanese and I'm always surprised when I start up new games and see which ones have some Japanese language content. I recently got ANNO: Mutationem on the Steam sale and thought "This is cheap and looks cool. I'll try it." without even thinking about using it for Japanese.
Turns out…this game is fully in Japanese with Japanese voice acting, script, everything. It's amazing. It is definitely for more advanced learners and those who know quite a bit of kanji (no furigana) but it's so immersive that I absolutely love it even though I don't always understand what's happening.
You're basically a skilled fighter in a cyberpunk world trying to find their brother. The game switches between beautiful 3D exploration scenes, cut scenes, and 2D platforming. You can talk to all sorts of people, buy weapons and upgrades, trade stuff. It's super cool.
by investoroma