Extra secrets to compensate for the missing levels.
The Nailgun and the Thunderbolt use different sound effects when they fire.
Has no "NIN" ( Nine Inch Nails) logo on the Nailgun ammo boxes.
Distortion effect in Fluids on weapons.
GLQuake looks better in some ways, however.
Less detailed maps, but graphics look better than vanilla Quake.
Weapons firing and other moving light sources do not light up rooms, but have a corona around them, similar to the default in GLQuake. are dynamically lit according to the colored lighting sources.
Colored lighting, but the lightmaps on world surfaces are pre-rendered.
Players did not lose their weapons when entering a new episode.
The player has to play through the levels in a linear order, and cannot choose a specific episode.
It is missing the following levels: E1M4: the Grisly Grotto, E2M1: the Installation, E2M4: the Ebon Fortress, E3M5: the Wind Tunnels, E4M1: the Sewage System and E4M5: Hell's Atrium.
Exclusive deathmatch level: The Court of Death.
Different music composed by Aubrey Hodges, but same style (ambient).
HUD is not a big box it only shows Armor, Ammo, and Health.
Split screen deathmatch for two players, but suffers heavy frame rate drops.
There is no Welcome to Quake, rather the difficulty is selected via the main screen.
2 Level Changes (Going by Hard/Nightmare Difficulty).