Hi-Fi Rush was stealthily released early this year during an Xbox showcase, and quickly became a huge hit with over two million players and raving reviews (including from us here at Gamereactor). Since then, we haven't heard much about its future, although it has been improved with quality-of-life updates, a Photo Mode and some other things.
Fortunately, it seems like Tango Gameworks and Bethesda is planning on doing something more with the game, as noted by the proven insider Dusk Golem on Twitter. No less than seven Achievements have been added to SteamDB, which are all secret.
Incidentally, Hi-Fi Rush also has a pretty generous discount on Steam right now, just before Summer Games Fest and Xbox Games Showcase. All things added, it does seem like Bethesda is planning some kind of content update, or perhaps even a full fledged expansion, to Hi-Fi Rush pretty soon.