Prospekt

Prospekt begins in the Nova Prospekt prison in the Half-Life universe. Gordon Freeman is slowly being overrun by soldiers in the prison, however unknown to him his Vortigaunt allies manage to find some help from a forgotten hero.

Substantial, highly-polished and totally new addition to the Half-Life 2 universe, comparable to Half-Life 2: Episode One in length
Developed by one person, 25 year old Richard Seabrook
Official Valve approval for Half-Life 2 license and assets
Standalone PC game built using the Source engine - no requirement for Half-Life 2
Continues the story of Opposing Force, Gearbox Software’s (Borderlands) update that tells the original Half-Life 2 story from the perspective of the Marines.
Gordon Freeman is cornered and being overrun by soldiers in the Nova Prospekt prison; the player controls US Marine Adrian Shephard - the unsung hero - as he’s teleported in by Freeman’s Vortigaunt allies to help fight back.
13 new levels featuring fully-scripted puzzles and action sequences, all carefully integrated into the Half-Life 2 story
Substantial graphical updates over the original game, including but not limited to:
New Textures
New Models
Updated high resolution Combine soldier skins with improved normal mapping
Updated high resolution textures
Updated lighting
Higher resolution models
Increased cube mapping
Over 20 new particle effects
Modded HUD
Modded VGUI
New player model skin
Return to Xen
New voice acting
New music
New AI improvements, such as soldiers attempting to undo the player’s actions