Two top iPhone games have slashed their prices to free, for today only, giving you addictive RPG and tower defence for absolutely nothing.

Fastar!, from Cat in a Box games, deals up all the traditional tropes of RPG - smashing random enemies for coins and spending dough on tiny upgrades - but distils them into a blindingly fast speed run.

Instead of tiresome number-cruching turn-based menus, you merely mash on enemies until they spew up currency. And instead of a massive monster dictionary, it's all just squares and other such malicious geometry.

TowerMadness, however, takes its source material a little more seriously with a very deep and faithful take on the tower defence genre. You’re tasked with blasting little alien men, as they try and nick your sheep. You need to erect turrets and keep them upgraded to fend off extra terrestrial foes.

It’s probably gone free, we reckon, in celebration of the iPad version’s massive new update. TowerMadness HD (which isn’t free, it’s £4.99 / $7.99 / €5.99) now has new free maps BarnYard and Diagonal, plus a Lava-themed map pack (with six stages), and will be available on the store soon.