The shooter is powered by the Doom 3 engine.
In an interview for IGN, Tim Willits of id Software has confirmed some of the details of their next big title, Quake 4.
The title will be a continuation of the Quake 2 ethos, rather than the Quake 3-esque multiplayer only affair. Tim is adamant that they have focused on making a corking single player game - adding in buddy-squads amongst other new features. However, multiplayer will also be a return to the Quake 3 days, rather than the slower-paced experience of Doom 3.
The storyline will revolve around the rising of a new Makron, following the destruction of the old one at the end of Quake 2. As a marine, you'll have to go in with your buddies and support infrastructure to take it out. According to id, the game will have an 'all out war' feel to it, with vehicles to back you up.
Making a welcome return is the rail gun, as well as some of the bad guys from Quake 2.
Engine-wise, Tim suggests that the only real changes have been made to scripting and AI, with the Doom 3 engine plenty versatile enough to handle the different setting. He also mentions that some of the level design that has been done makes Doom 3 look 'plain'.
The gameplay is being handled by Raven software, who have long collaborated with id on titles using their technology, right back to the Hexen days.
Whilst we are expecting the game later this year, id are sticking to their 'When it's done' mantra.
The full interview is here