Ok this one is really easy in principle -- all you need are 3 jumps (green) and a shield (purple).
Now play the game as normal saving your powerups and pay attention to the clouds. When you see a nice patch of 3 or more that are nicely packed together and reasonably low to the ground, just slam your ship into something. With any luck, the shield will respawn you at about cloud height, and you can use your jumps to stay airborne long enough to hit 3 of them.
One thing I noticed from my many failures, is that I tended to repawn lower to the ground if I jumped before crashing vs just slamming into something at ground level. Not sure if it's coincidence or not, so take that advice with a grain of salt.
Also, as Johnny Sinister pointed out in the comments: the clouds in the Misty Valley bonus level do not
count towards this achievement.
Now all that said, this can be annoying as butts to actually pull off, so try not to get frustrated if you end up spending too much time on this -- I certainly did... a woefully incomplete list of ways I've botched this follows:
- It suddenly becomes a beautiful sunny day with clear skies for miles
- The only clouds spawn between levels where you can't crash into anything
- Your shield respawns you too low to the ground and you go under the clouds
- Your shield respawns you too high in the air and you go over the clouds
- The clouds are a bit farther apart than you thought and you only hit two of them
- Any number of jumps not making your ship go where you thought they would
Here's a video for all the visual learners out there:
Sorry, this Game Clip has been removed
Hope this helps, had to relieve a bit of pent up salt there