I built a browser thing called densha: a voxel Tokyo made from Japan’s open PLATEAU city data, with the real Yamanote loop running through it. You board a train, and as it rides, N5 sentences play with audio and furigana, polite and casual forms, English a beat later. Lofi in the background, a chime at each station. The world follows real Tokyo time, weather and season, so after ~1am the trains stop running.
Free, no account, works on phones: densha — study Japanese in a living voxel Tokyo
Full disclosure: I’m building it (JIVX). It’s not a replacement for anything, more a study room to leave open while you do your reviews. Feedback welcome, especially on mobile performance.