After eight years of work, fans are about to release an updated and expanded version of classic video game Half-Life.
Called Black Mesa, the resurrected game will be made available as a free download on 14 September.
The update has been put together using programming tools released by Half-Life creator Valve.
It will have improved graphics, better physics and environmental effects and a tweaked story line.
News about the long-awaited update broke at the weekend when a countdown timer appeared on the Black Mesa project webpage.
A forum message posted soon after revealed that eager players would not get an improved version of the entire game on 14 September.
Carlos Montero, leader of the 40-strong Black Mesa development team, said it decided to release a shorter version instead of making people wait longer for the whole thing.
The large chunk of Half-Life that is finished lets players guide hero Gordon Freeman to a section of the original gameplay known as Lambda Core. Finishing this first chunk should take players between eight to 10 hours.
The final section yet to be finished takes place in the alien Xen dimension. An expanded Xen section would be released at an unnamed date in the future, said the team.
First person shooter Half-Life was released in 1998 and gave players the task of guiding government scientist Gordon Freeman through the Black Mesa research complex battling aliens and thwarting their attempt to invade Earth. The game has been hugely influential since its release.
Half-Life creator Valve released an updated version of the game in 2004 that was built around its Source game code or engine. That official update of Half-Life was generally regarded as unsatisfactory and led to the Black Mesa project which aimed to do a better job.
The project uses an updated version of Source which leads to improvements in physics, lighting and allows for far more subtlety in the facial expressions of characters.
The Black Mesa team has also edited the storyline to beef up the more engaging parts of the game and eliminate the slower parts.