Fun concept!
Great implementation of the theme, concise gameplay loop, great implementation of the theme, fun to play.
As feedback, I'll agree with the other comments about running. If you always have to be running there's no reason to force the player to hold shift.
Maybe some way of highlightning passengers making them easier to find?
Sound is important for game feel. It's good to try and squize some in, even if just one sound or music.
Anw, great game!