The long-awaited Black Mesa modification, a revamped version of Valve's original Half-Life game from 1998, will be available through Steam's Greenlight service later today.

Originally announced in 2004, Black Mesa started production as a protest against Half-Life: Source, another remake of Half-Life which many fans felt was disappointing.

Built using a 2007 version of Valve's Source engine, Black Mesa uses similar technology to Half-Life 2 and features advanced particle effects and more detailed facial animation.

But despite promising early trailers and a great deal of anticipation, development of Black Mesa has faced problems. According to an interview with project lead Carlos Montero on Rock, Paper, Shotgun, organising a team of forty designers all from different countries slowed production dramatically:

"In a manager-centric team, every layer of management is technically a bottleneck, a pipe that all work must get through. In a global multi-time-zone environment, this effect is magnified many times over. It really didn't take much to realize that having people in global locations struggling in vain to get in contact with someone because of timezone differences was a bad thing.

"Trying to organize who did what, what people were supposed to be was a logistical nightmare. If you are waiting on someone to tell you what to do or approve something, and they are never available when you need them, everything slows down drastically.

Black Mesa

"This project started as a 'Half-Life HD' of sorts, but it's really grown into more of a re-imagining of Half-life with an emphasis on using what we as an industry have learned in the last decade...It has confused our design approach and structure over the years, I think. There are probably people on the team who would wholeheartedly disagree with those sentiments though."

A large portion of the original Half-Life story has also been rewritten and updated for Black Mesa, as well as the musical score. However, a complete version of the game will not be available immediately, with the Black Mesa Modification Team currently offering "8-to-10 hours" of content, according to NowGamer.

Players will be able to reach the final third of the Half-Life story, during which they are transported to an alien world called Xen. The Xen chapters themselves are expected to be released at a later date.

Although the game will be available to download for free from Steam later today, eager fans can go to the developer's own site and access Black Mesa early.

IBTimes UK will be reviewing Black Mesa next week.