To celebrate its 40th birthday, Atari is allowing iPhone and iPad owners to play all 100 titles featured in its Atari's Greatest Hits iOS title completely free of charge.

This application has always been available for free, but you'd normally have to make a £6.99 / $9.99 in-app purchase to download its entire library of classic arcade and console hits, which include the likes of Asteroids, Centipede, Crystal Castles, Pong, Red Baron, and Super Breakout.

Be warned, though: these titles will only remain free so long as you don't delete the Atari's Greatest Hits app from your iPhone, iPod touch, or iPad. So, you should keep it on your device for as long as possible, especially if you own an iCade arcade cabinet.

Grab Atari's Greatest Hits from the App Store for free.