Thank you for the feedback :) Yes I guess we definitely need to do something about the difficulty. We had different difficulty obstacle patterns in mind so we can spawn easier ones first but we were pretty close to the deadline and had to postpone that idea :P One thing we also played around with was camera position, because it feels much easier the earlier you see the obstacles you need to avoid.
Implementation wasn't too easy because we were not able to use unitys build in physics (Because of the curved line) and had to more or less implement a new 'curvy' coordinate system. The UI is basically just a bunch of gameobjects living in that 'curved world' with colliders on them :P