Really good foundation, would love to see this one completed! 
The driving itself felt really good. Took me a while to find a passenger, and then I had no idea where to take them. 
Also found a building with no collision.

But there is a really solid foundation here. The driving handles nice, and with some way markers or an arrow making it easier to find passengers or their destination, I think this would be great. 

Nice concept! Like others have already mentioned, there are a few bugs on the main screen. Even in the game, I wasn't sure what was I supposed to do. The music was good and the mechanics were good as well! Good job on that!

Game was unplayable. Every time I hit the back button in the menu, nothing happened. I had to kill the game three times just to get through the menu. When I started the game, it showed a car select screen for a second and then bypassed it so I couldn't choose my car. Once I got into the game there was nothing to do and the music stopped working. Great music choice on the main screen though!

Ok. I'll start with problematic thing and after good things
Problems:
Game info button doen't work, so I need to reload a game to get to it) 
I undestand you wanted that cool GTA3 look, but it caused unreadable texts of delivery system. 
I didn't understand a green balls meaning, I feel like they should be a navigational tool but they are not really helping. 
Coloring of deliveries is probably intended to be different. 
Radio stops working. 
There is no tire sounds. 
Now good things:
I really like overall graphics I think it nails a feeling of GTA3. 
Figure of a passenger litterally above a car is probably a bug but it could be a feature, maybe you can scale it smaller and has reaction to driving. 
Overall mechanics is working. 
Making a taxi simulation is really a massive task for a single person, and I think you did your best. Thank you for sharing your work. General advise is to use FMOD for car simulators. Cause they has a complicated sound system.