E3 Reconstruction Mod ports Half-Life 2 E3 2003 maps to retail HL2 engine along with all the content (models, textures, code) they depend on, while remaining faithful to originals.

Aside from maps themselves, other minor features are:
- Beta weapons: restored beta weapons are currently Physgun, OICW, Flare Gun, I-Rifle and Sniper Rifle. Shotgun uses its beta model and sounds.
- G-Man, Combine Soldiers have their beta skins.
- Changed certain AI code to make NPCs work better with E3 maps.

Mod's page on Mod DB