Game Design documentation:

The current game design documentation can be downloaded/Viewed here (PDF)
Spoiler Warning: This document contain the story of the game.

Quick description of the game levels:

The game contain 9 levels. I'll describe here the first 3 levels

Objectives:
(First Level - Gizea Plateau)

Try to inflitrate the site, gain access to the digger robots, reprogram them and lauch them. The player will not have any weapons. He will have to find some weapons from the soldiers there.
Concept art by Christian Clavet

(Second Level - The Dig)

Robots start digging. Protect them while the soldiers are alerted by the noise. Enter the tunnel and explode the entry. Will have to follow the robot while it dig.

Concept art by Christian Clavet

(Third Level - Entrance to the secret tunnels)

Robot digger dig into a water basin, the tunnel is getting filled with water fast, the player have to go thru the end of the tunnel and swim up the the basin.
There will be the entrance to the underground tunnels under the pyramids.