Despite being released back in December 2009, the titan of iPhone gaming, Angry Birds remains in the top 3 of the overall sales charts, with its spin-offs Angry Birds Seasons and Angry Birds Rio also in the top 10.

This means that many, many people are still discovering the wonderful mix of fun and frustration to be found among those seriously narked birds.

And that of course means many, many of you stuck trying to complete a level and the purists trying to earn the full 3 stars. While you could buy the Mighty Eagle, help is at hand from Rovio’s videos giving you a walkthrough.

Below we’ve embedded the final levels from Poached Eggs with level 21 proving particularly tiresome for us.

You’ll find walkthroughs for levels 16, 17, 18, 19, 20 and 21 in theme 3, sure to relieve much of the frustration, although from our experience you’ll need a few tries to hit the sweep spots required for each level.