Here is my 100% Achievement guide for Hardcube!
This is extremely simple!
When we start Level 1-1, jump to the left over the tiny barrier looking thing and fall down.
Do this 15 times to get 2 achievements in 30 seconds!
You CAN do this on the tutorial level if you wish to get it out the way quicker, but i wait til level 1-1
Go to 3:10 in my video to see exactly where i get this!
Hope This Helps!