This is a sub-page of Proto:Half-Life (Windows).
Graphical DifferencesThe lone nipple that remains.
Weapon and Item DifferencesEntities#
Alien Slave#

The Day One Alien Slave has some unique animations missing from the final game, including some that suggest that the Alien Slave could be grabbed by Barnacles at one point. Its textures are also at a higher resolution than in the final game.





Bullsquid#

The Bullsquid has some animations that were removed from the final game.





Day One |
Final |
|---|---|
eye2.bmp shows its pupil slightly more centered than in the final game.
G-Man#
120px|right Watch on YouTubeThe G-Man is in Day One, but he has an odd behavior that was cut from the final game. When shot enough, he will run away very fast with a running animation removed from the final game.
While this sounds funny and harmless, it causes a problem in the middle of Unforeseen Consequences. Shooting G-Man to the point where he starts to run during his Unforeseen Consequences appearance will prevent him from despawning. This prevents the player from leading the scientist near G-Man's location to the ammo-filled room to unlock it because G-Man is in the way.

Headcrab#
The Headcrab has a slightly different set of textures than what it ended up getting in the final game. Its textures are whiter, and it has four eyes instead of the final's six.
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Prototype |
Final |
|---|---|
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Human Grunt#

Generally, Human Grunts are more interested in killing the player than killing scientists. This can cause some issues, such as during the sequence where the player first encounters the Human Grunt.
In Day One, the Human Grunt model uses textures of high quality compared to the final game version. The backpack texture is less pixelated and has noticeable pouches/pockets and the bottom part of the left pant leg has a slightly different camo pattern. The animations and the textures are all contained in the model itself, while the final game splits them up into groups.
Human Grunts only have the white gas mask head and the beret heads in Day One. The gas mask texture is significantly different from that of the final game, it is nearly identical to the one used by the friendly Human Grunts in Half-Life: Opposing Force.
Human Grunts do not use the Shotgun, and don't even have it in their model file. This is likely because Human Grunts armed with shotguns make their first appearance in the chapter On A Rail and the demo ends before the player reaches that chapter.
For some reason, the victorydance animation is a slowed down, duplicated reload animation. The frontkick animation is slightly slower and has extra frames. Both the 180L and 180R animations have the grunt actually rotate his body; in the final game the animations lack that and the rotating is instead done via code.




Human Grunts have a number of unused animations.








Scientist#

The Day One Scientist has several animations that the final Scientist model does not have.







Security Guard#

The Security Guard has many animations that cannot be found in the final's Security Guard model.






Zombie#

The Zombie has animations that do not appear in the final game.



Player#
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Most of the animations in the Player model are completely different from the final version. The model itself is the same as the final.
It has one unused animation of particular note, "ambushplayer". This was meant to be used in conjunction with the Human Grunt's "ambush1" and "ambush2" animations in a third-person sequence meant for the chapter "Apprehension" in the section where Gordon is captured by the HECU. The full 3DS Max file for this scene was leaked in 2024.
The model also has two bodygroups ("gender" and "weapons") that are not in the final version. The gender bodygroup allows the model to switch from Gordon (the default model) to Gina. This was likely intended for the cut cooperative multiplayer mode. The weapons group is similar to the equivalent bodygroups on NPCs; it has choices between the Shotgun (default), the SMG, and no weapon at all. The final game uses p_ models to show weapons in third person. Also, for some reason, the SMG submodel is backwards.


Maps#
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c1a0e#
Meeting the Alien Slaves#
In build 676, the area seen during the Resonance Cascade in which Alien Slaves surround the player is brighter, its walls can be seen with a flashlight, and the player's movement is not blocked.
c1a1g#
The map files of build 693 onward include c1a1g, an unused map containing the entrance to the Anomalous Materials lab. In the final game, this area is a part of c1a1f. However the map is used in Half-Life: Source.
c1a2#
Path to the Storage Room#
In build 676, the path to the storage room and the door the Zombie breaks down are both on the same path in the prototype. Build 693 and the final game split them into two separate paths.
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Prototype |
Final |
|---|---|
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Missing Boxes#
The corridor to what is c1a2d in the final game does not have any boxes and is much shorter in build 676.
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Prototype |
Final |
|---|---|
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c1a2d#
c1a2d is merged with c1a2 in build 676.
c1a3#
Invincible Scientist#
The scientist that bangs on the window, then runs into the Tripwire Mine behaves differently in build 676. He will only die after leaving the SMG room. He'll run through the Tripwire Mine without a problem, then stand in front of a chain-link fence and absorb Sentry Gun bullets without any problem until the player leaves the SMG room.
Build 693 and the final game fix this by having him automatically die soon after he runs past the Tripwire Mine or soon after he stops in front of the chain link fence.
First SMG#
In Day One, a dead security guard can be found next to the SMG at the start of We've Got Hostiles. The final game changes it to a dead Human Grunt, likely because security guards are never seen using SMGs and a dead Human Grunt lets the player see one before they start appearing in full.
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Prototype |
Final |
|---|---|
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Vents in SMG Room#
The SMG room in build 676 has two unbreakable vents that were removed in build 693 and the final game.
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Prototype |
Final |
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Prototype |
Final |
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Cafeteria Table#
The table in build 676 will break into two pieces if the player jumps on it. After destroying it, the sides are not fully flattened, which can be fixed by jumping on it again.
Build 693 and the final keep the table, but move it slightly and the player cannot jump on it to break it in half.



c1a3a#
First Human Grunt#
In Day One, the first Human Grunt the player encounters will begin attacking the player as soon as the player comes into sight, ignoring the scientist running down. The final game fixes this by having the Human Grunt wait for the scientist and attack him, then go for the player once the player gets closer.
Strangely, Half-Life: Source undoes this fix and has the Human Grunt attack the player while ignoring the scientist.
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Prototype |
Final |
|---|---|
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c1a3c#
Time of Day#
The Day One C1a3c takes place during the day, while the final one takes place at dusk.
This is kept for C1a3d as well.
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Prototype |
Final |
|---|---|
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Prototype |
Final |
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c1a3d#
Ending#
The large vent at the bottom of the map has a large grate in front of it, preventing the player from continuing. This marks the end of Day One.
Oddly, the game will only begin the fade out/ending sequence if the player starts climbing down the yellow ladder that leads to the bottom of the air shaft. If the player jumps directly to the bottom catwalk, the game will keep on going until the player goes to the top of the yellow ladder.
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Prototype |
Final |
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Videos#
Day One comes with two videos removed from the final game. They show Gordon Freeman and Gina's models rotating 360 degrees.
Of note is the fact that both carry helmets. In the final version there is no indication that Gordon wears a helmet.
gina.avi#
gordon.avi#
Difficulty Differences#
The prototype has some differences in how much damage enemies do and how much health they have in each difficulty.
Of note is that the Gonarch and Alien Controller are not listed in the skill.cfg file at all. The Day One version of the file also lacks listings for medkits, batteries, health and HEV chargers, and the amount of damage the Nihilanth does.
Easy#
Parameter |
Day One |
Final |
|---|---|---|
Alien Grunt Health |
100 |
60 |
Alien Grunt Hornet damage |
4 |
5 |
Alien Grunt Hornet damage |
4 |
5 |
Gargantua Health |
2000 |
800 |
Gargantua stomp damage |
25 |
50 |
Female Assassin health |
50 |
30 |
Human Grunt damage |
3 |
4 |
Icthyosaur Health |
80 |
200 |
Icthyosaur melee |
10 |
20 |
Nihilanth Health |
200 |
800 |
Scientist Health |
8 |
20 |
Normal#
Parameter |
Day One |
Final |
|---|---|---|
Alien Grunt Health |
100 |
90 |
Gargantua Health |
2000 |
800 |
Gargantua stomp damage |
25 |
100 |
Icthyosaur Health |
80 |
200 |
Icthyosaur melee |
15 |
35 |
Nihilanth Health |
200 |
800 |
Scientist Health |
8 |
20 |
Hard#
Parameter |
Day One |
Final |
|---|---|---|
Alien Grunt Health |
100 |
120 |
Alien Grunt Hornet damage |
4 |
5 |
Alien Grunt Hornet damage |
5 |
8 |
Bullsquid Health |
80 |
120 |
Female Assassin and Security Guard damage |
5 |
8 |
Gargantua Health |
2000 |
1000 |
Gargantua stomp damage |
25 |
50 |
Human Grunt damage |
4 |
5 |
Icthyosaur Health |
80 |
400 |
Icthyosaur melee |
15 |
50 |
Nihilanth Health |
200 |
1000 |
Scientist Health |
8 |
20 |
Version Differences#
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