A good start I'd say.

I don't play many similar games, still remember taxi games and the classic "Paperboy".

What I'd like most as improvements are a world where the physics are a bit more polished (smoother ground, no sudden jumps/turns due to physics/bike behavior), maybe some small elements the bike can interact with (jumps, puddles, physics/destructibles, etc that add a touch of "biking here feels nice").

And maybe you can come up with ideas what it's like to deliver in NY. Traffic is probably too hard to add as a next step, maybe something that is about how you switch from sidewalk to street or the other side.

Something like Paperboy is maybe also fun - I agree rather a quite random idea:  The biker can throw something (keys Q and E or so while not interacting!?), doesn't have to be the newspaper, and if you (roughly) hit the right spots you get a score or dollars (flyers the restaurant gives you, flyers from the gym, could be anything that can be delivered by throwing). :) 

Keep up the good work!