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Half-Life: Day One

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HL Day One menu
Half-Life: Day One

Valve Corporation

Release date(s)

November 1, 1998[1]


First-person shooter






Valve Corporation

System req

500 Mhz processor, 96 MB RAM, 16 MB video card


Keyboard and mouse





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Half-Life: Day One is the initial pre-release demo of Half-Life. It was designed exclusively for OEM partnerships and was often bundled with graphics cards. It was never available to the general public. Half-Life’s proper demo (available free to the general public), is Half-Life: Uplink, which was released several months after the full game.[2]


Day One begins at the same point as the full game (and has the same storyline), but ends after the player completes the chapter "We've Got Hostiles", at the end of the first day of the game's plot. The levels accessed in this demo are overall identical to those that appear in the full game.


The demo does have some minor differences from the retail version of Half-Life.

  • The console and cheats cannot be activated.
  • Direct3D is not supported (Only supports Software mode and OpenGL)
  • The files stored in the .pak files have priority over the files placed in the actual folders.
  • Up to 25 grenades can be carried instead of 10. Additionally, they don't explode in the player's hands if they are cooked for too long, and it is possible to throw them further than the retail version.
  • The Glock 17 pistol can have an additional round in the chamber after reloading a non-empty magazine, increasing the capacity to 18 rounds.
  • The MP5 already has 50 loaded rounds when picked up.
  • The Valve theme (officially known as Hazardous Environments) plays when picking up the MP5 for the first time.
  • The shotgun doesn't get 4 extra shells in reserve when picking it up.
  • The shotgun's pump sound is always heard at the correct time.
  • Picking up ammunition for the pistol or the shotgun grants the player 30 extra rounds instead of 17 and 12.
  • The Long Jump Module shown in the hazard course looks like a HEV battery with a red color instead of a jetpack.
  • The HEV battery has a different appearance.
  • Neither the pistol nor the MP5 reload automatically after emptying a magazine.
  • There is no secondary attack for the pistol; it can only fire in semi-automatic mode.
  • HUD sprites found in the Day One files feature an early RPG icon, an unused battery-style HEV suit indicator as seen in E3 1998 videos, fewer sprites for 320 screen width and 320x sprites that do not feature the bar near the man showing suit power.
  • The HECU Laser Tripmine uses the E3 1998 model. Though seen in "We've Got Hostiles" the player never got to use it as a weapon (since the Tripmine is obtained at the end of "Blast Pit", which isn't in "Day One")
  • Zoom can be toggled by pressing F11.
  • When the player reaches the surface in the chapter "We've Got Hostiles", it's daytime instead of sundown.
  • The access to the storage chamber in the beginning of "Office Complex" (when the shotgun is first found) is not blocked by boxes. The storage chamber itself, is also a part of c1a2
  • There are more vents in the area where the MP5 is found in the chapter "We've Got Hostiles".
  • The area seen during the Resonance Cascade in which Vortigaunts surround Gordon is brighter, its walls can be seen with a flashlight and the player's movement is not blocked.
  • "screenshot" command saves screenshots in broken 8-bit PCX files, while the final version saves them in TGA format. "snapshot" command works the same way as in the final version.
  • Upward looking is limited. (Because of this, if Gordon is caught in the Barnacle's tongue, he cannot kill it until the barnacle inflicts damage.)
  • Blood effects are different: in Day One blood is flowing (like Half-Life Alpha 0.52) while in retail it is splashing.
  • Autoaim is enabled by default and cannot be disabled.
  • In "We've got Hostiles", the G-man has a different reaction when being shot by the player. If he is fired upon enough times, he will grab his briefcase to his chest level and run, apparently scared from the bullets, to the area containing the elevator. This is either an easter egg removed from the final game, or implication that Gordon was to come in slightly more direct contact with him, or even that an event would occur where the G-man runs away. His "running" animation was still in the final version although not used.
  • The HECU troops only feature the beret and gasmask soldiers, and they don't use the shotgun as their primary weapon.
  • The death of the Bullsquid features the creature flipping upward, similar to the Headcrab, but in some cases it dies like in retail.
  • At the ventilation shaft where the game ends, even if the player tries to reach the bottom vent quickly, it is blocked by a fence thus cutting off access.
  • Barney also have different walking animation. Some Animations in Barney's .mdl file (Which can be seen in Half-Life Model Viewer) were cut in Retail/Steam version of game.
  • When grenades hits the floor, it's gives Satchel's sound effect.
  • Every characther has Beta animation in Day One that not includes in Retail/Steam Version.




  • Glock 17: The most common handgun.
  • Crowbar: The most iconic weapon of the series. Can be used to break crates and weapon boxes, as well to kill enemies.
  • Mk 2 Grenade: The most common used hand grenade. Can be thrown at enemies for an explosive radius of damage.
  • HECU SPAS-12: The most common shotgun used by the HECU. It has high power and causes high damage.
  • Laser Tripmine (Not usable): A laser tripmine device that explodes upon movement.
  • MP5: The most common automatic firearm used by the HECU.


  • It is not possible to activate the console, however it's possible both to enter console commands and to see console output.
    • To enter console commands, "gfx\shell\kb_act.lst" file should be extracted from "valve\pak0.pak", a new line in "command" "any name" should be added to kb_act.lst, kb_act.lst should be added to "gfx\shell" of pak0.pak, and a key should be bound to a new command in the main menu.
    • To see console output, the game should be launched with -condebug command line argument. The output will be written into "valve\qconsole.log".
  • Day One DLLs were built on August 31, 1998, and the executable file was built on September 1. Its build number is 676. It is OEM Release Candidate 4,[3] however, the text in top-right corner of the console (cannot be seen in game but can be seen inside engine DLLs) says "Half-Life 1.0 Alpha build 676", possibly a leftover from alpha builds. Executable file version is, possibly referring to its Release Candidate number, but version range 4.x was later taken by dedicated server version of Half-Life.
  • This game allowed players to carry up to 25 grenades, instead of 10. This probably explains on why more than 10 grenades can be found in certain locations. Moreover, grenades can be thrown further.
  • By interacting with the scientist to open the security door:
    • If the player attempts to access the area where "Blast Pit" was supposed to load, it will cause the game to crash because the game couldn't find a Blast Pit map.
    • If the player accesses the room with the MP5 ammo, the scientist in the freezer room will be alive instead of being dead.


External linksEdit


Half-Life Wiki has more images related to Category:Half-Life: Day One screenshots.

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