Beautiful game, but...
I find that it lacks progression and it just doesn’t get any harder. I have had the game for only 3 or 4 days and I just played a game and got 635... it needs to speed up or something to make it more difficult. If not that approach then I would recommend introducing a risk-reward type system: adding jumps & rails to the bridges that double points for a short period is an option. I used to find the game incredibly fun, but it has started to become monotonous and a bit boring. Hope this feedback helps.