Is my Steam bugging out or is this like a HUGE game for the short playing time?

I boot the game and am greeted by this screen: https://i.imgur.com/sRDLTMQ.png After a few seconds the window resizes from fullscreen to a smaller borderless window and music and sounds start playing. Clicking in the window resets it back to fullscreen. Music and sound continue to play over the loading screen. Waited for a few minutes more as music and sound continue to play, no change. Opening and closing the Steam overlay leaves a greyed-out version of the overlay on top of the loading screen. Clearly so...