Nice one, it feels fun cruising around and the game truly shines later on with the "timed" intersections later on, it's a clever take on the theme for sure, i'd say since you have the "Only One" aspect in your controls, you could have the player be able to take some damage instead of a one hit death, and have maybe some penalties on a timer or score when you hit other cars or people, this could mix things up a bit and add some fun, also nice to have included an options menu for scalability ^^
It felt pretty solid and i enjoyed it, you say One button GTA, but it also feels kinda like a One button Reverse Carmageddon :p (both are fine by my book )
Congrats dude :)