The world is slightly larger.
There are 500 somethings scattered around for you to collect.
The game now saves everything the first time you start it up and again any time that you find one of the collectibles.
It loads that save file when you return to the game.
Every building now has at minimum one door on the ground floor.
Every building now has an elevator.
There are now skywalks connecting even buildings that are immediately next to each other.
There is a mini map of the city (it doesn’t rotate or zoom or show your position on it or do anything like that yet).
There is a ghost mode added for testing purposes in which you can fly forward with collision detection and gravity turned off (press down to enable/disable it).
I think that is everything aside from some less noticeable tweaks (turning is faster for example and sewer manholes are slightly wider and I removed some unnecessary polygons from the walls).