I think the ten minutes is a bit too long, personally, I believe it would be best if the hazards ramped up a bit faster. The character is a bit too slow by default in my opinion and while the speed-ups do help, once they run out, the game feels 100x slower than before. If you want to continue with this idea, I would probably add obstacles in the city, like houses with some walls inside or something. Also a tornado spawned right in my face at least twice, it felt a bit unfair. Other than that, I think the movement was well made and the idea is reasonable. Good job!