Introversion releases source as Humble Bundle bonus

British coding legend Introversion Software has become the latest independent developer to take part in the Humble Bundle, releasing its back catalogue under a 'pay what you want' scheme to raise money for charity - and it's giving away the source code, too.

Introversion - which comprises friends Chris Delay, Mark Morris and Thomas Arundel - shot to fame upon the release of Uplink, a Hollywood-inspired simulation that saw the player take on the role of a hacker working to uncover a shady plot to destroy the internet.

With the tagline "The last of the bedroom programmers", Introversion's first game was as independent as you can get: CDs were burned on consumer hardware and fitted with home-printed labels, while the case inserts and manual were printed on a low-quality inkjet printer.

Despite its humble origins, the game was a smash hit. Sadly, the company soon burned through the cash generated from its release - largely thanks to one of its biggest distributor refusing to pay royalties and then filing for bankruptcy - and struggled to release its second game, Darwinia.

Getting Valve involved and launching Darwinia - and, later multi-player variant Multiwinia - on the Steam digital distribution platform proved to be a success, funding development of a War Games-inspired strategy game called DEFCON.

The company currently has three games in development: Subversion, a spiritual follow-up to Uplink with shades of turn-based tactical shooter Frozen Synapse, Chronometer and Prison Architect, but silence from the company in recent months has led many fans to worry that it is once again running low on funds.

It's not surprising to see the Introversion turning to the Humble Bundle, then: previous sales have seen independent developers earn thousands of dollars in a matter of weeks as their games are sold on a pay-what-you-like basis.

As with previous releases, buyers can choose where their money goes: the default split sees the original developers receiving a portion of the proceeds, along with charities the Electronic Frontier Foundation and Child's Play, with a small final cut going to the Humble Bundle team.

Thus far, the offer - which runs for the next six days - has seen a rapid uptake: with almost 154,000 sales, the bundle has generated $610,000. Linux users have again proved the most generous, paying an average price nearly three times that of Windows users, and just under double that of Mac OS users.

It's not hard to see why: as well as copies of Uplink, Darwinia, Multiwinia and DEFCON, buyers who pay more than the current average of $3.98 also get access to Crayon Physics Deluxe, Aquaria and Dungeons of Dredmor.

The biggest surprise, however, comes in the form of a gift from Introversion itself: all buyers get free and unrestricted access to the source code for Darwinia, Multiwinia, DEFCON and Uplink - allowing improvements to be made, spiritual sequels to appear and even ports to other platforms such as iOS and Android to be considered.

It's a major move for Introversion, and one that has been universally welcomed by its fans. If you need to be convinced regarding the merits of the company's output before heading over to the site and making a purchase, however, there's a trailer video below.