Start level 18 "Edge Time", and progress until the final button. Just after pushing it, fall down that block and edge it eight seconds. It should appear as if you are the human's backpack.
Easy "Minimalist" Achievement
Go through the level as usual. When you reach the nine switches, press the one at the middle-left. Then, quickly climb on the block that appears on your left. If you fail, fall off the level and try again.
Easy "Nailed it" Achievement
Hit the button halfway through bonus level 2, "Hammer" before it disappears. To do this, rush through as fast as possible. The switch is about the halfway point with 3x3x3 cubes, with a hole in the middle. One of those cubes has a button that eventually disappears. Hit that button. Falling off the level forces the switch to rise to where it was in the checkpoint.
Easy "Stardom" Achievement
You must earn an "S+" rank on normal levels 1 through 45. To do this, you must get all prisms and reach the goal below a certain time limit. Do the following to save time. Edging time does not count towards the total. If you edge every time you climb, you will save between half a second and a full second each time. If you can edge, you can wait cycles until you are sure (specially in late levels that are longer) or arranged in a way that you are familiar with. If you die near the place where you respawn, you will not lose too much time. You will lose even less time if you were edging there.
Easy "Backpack" Achievement...