The classic Mac first-person shooter Marathon will soon be released to iPad owners free of charge via the App Store.  Ex-Microsoft outfit, Bungie Software, has recently posted an interview on their site with indie iOS game developer and (obviously) Marathon fan, Daniel Blezek.

Blezek has spent the last year on a labour of love, porting Bungie's 1994 sci-fi shooter over to the iPad. Whilst he will not be receiving a penny for his efforts, the game's original developer is behind him 100%.

Players should expect to tie their fingers in knots and/or suffer severe thumb cramp. As with the original game, which didn't utilise a mouse (befitting the iPad design), Marathon uses a complex combination of buttons to control the in-game character. These controls have been re-imagined on the iPad with the player's left thumb controlling a virtual joystick while the right controls the primary and secondary fire button.

Unlike modern shooters, Marathon employs old-school sprites to represent the invading aliens, known as the Pfhor. Blezek has carried this over to his iPad version. He has, however, added an optional aiming reticule which wasn't present in the original.

Windows and Mac owners can download the freeware Marathon trilogy here. Xbox 360 owners will find a version of Marathon 2, called Marathon: Durandal, available for purchase from the Xbox Live Marketplace.

Marathon rightly deserves a place in gaming history. It was this game, along with its successors and the first two games in the Myth series, that paved the way for Bungie software to go on and create one of the greatest game franchises of all time. The Halo series is widely considered the Xbox 360's killer app. Microsoft liked the game so much that it bought the company, although Bungie and Microsoft amicably parted ways in 2007. In 2010 Bungie signed a ten-year publishing agreement with Activision.

Look out for Marathon in the App Store soon.