To get all the achievements easily I simply played level 2 and grabbed the rightmost gem and the topmost gem by the exit. hit space at the exit to complete the level then click the restart button in the top right to restart the level. grab the gems again, complete the level and you should get 2 more achievements again, rinse and repeat until you have them all.

If this doesn't work for you then the best I can say is that I did a lot of random restarting of the levels and the game, also jumping around randomly from level to level until it bugged out and was showing the incorrect amount of gems I've collected on the levels. so maybe try that and then do the above method.

hopefully that works for you and you too can get all the achievements and be done with this horrid game. happy hunting.