Hi Oldof Hedman,
Actually the levels are results of procedural generation. They are not the same every run.
But they are...
They might be procedurally generated, but the seed is the same, so the hills of each island are the same each run, and so is the placement of any power-ups.
At least that is how it looks to me... Would be if they change from day to day, but in several playthroughs right now, with quits in between, I'm 100% sure the hills and powerups are the same each run.
That was one of the things that made me enjoy it, since I'm not really a fan of the randomized levels of classic endless runners. (though jetpack joyride is also awesome )
Ok, seems they do change, but only daily, for graphics and powerups. Hills are supposed to change too, but slower...
Probably has some theme-parameters for each island too, since island two always has these slopes that looks like the beginning of the end slope for example.