this solution is for the updated version of the game with the level select map.
go to level 4. you have to collect 3 clues and the relic to complete the level. instead, just run for 1500m while avoiding clues and sliding. it should only take about 2 and a half minutes. there are no places where you have to slide on this level. since it's an early level it just repeats a set of easier sections. the in-game achievement should pop up during the level once you reach 1500m. (NOTE: some people reported taking a bit longer, around 2500m.)