When you leave the save room, there are four zombies in the prototype, whilst the final has no enemies whatsoever. The door was also flipped.

In the prototype, no music plays here, but in the final, "The Underground Laboratory" starts playing.

The final version gave this part of the corridor a green tint.

This background had several changes made to it. The final version changes the red on the door to green, removes the light above the door, amends the colors of the rails and one of the pipes to the upper left of this background.

In the prototype, this is where "The Underground Laboratory" starts playing, but in the final it starts in the previous room.

Same changes here, but some of the stuff at the bottom of this background was amended.

This room was made slightly darker in the final, despite the light above the entrance being made longer.

The prototype had some red lighting on the floor here, but the final removed it. The biggest change here is that the lights above the entrances were changed. They're both white in the prototype, but where changed to blue and red for the final.

These two catwalks have some differences in the placement of the doors, but the main difference is the final added some blue and red light strips to the floors. The lights above the doors also had the colors changed, and parts of the background were made darker in the final.

This background in the east wing corridor had the door changed for the final. What was a red light on the wall becomes a longer, blue light for the final, and the room was brightened up slightly.

All the lights in this room were changed for the final. The text on the wall was also changed -possibly because a word was spelt wrong! In the prototype, it reads "LABORATRY EAST AREA", whilst in the final the laboratory text was removed, and the east area text was made larger.

The prototype is missing the snow the final has for these two backgrounds, in addition to the usual light changes.

The lack of snow is also seen on the prototype's door opening animation.

In the prototype, it's not obvious which console you're supposed to use here, the final makes it clearer by adding a blue light to it. The final also has a first aid spray on the barrel, which the prototype lacks.

When the robot arm does its thing, you don't get cutscene borders in the prototype, but do in the final.

When you go back to insert the fuse, Leon will be onscreen as it screws into position. He doesn't seem to be there in the final.

When the power is restored, there are some additional shadows to this room in the final, which weren't there in the prototype.

The prototype also has a glitch were Leon can overlap part of the background here, which the final fixed.

The west area corridor has similar changes to the east area corridor -lights on the walls were altered, and this door was changed.

Again, the text here was changed, getting rid of the "LABORATRY" typo and making the west area text larger. The text was orange in the prototype, but changed to red for the final.

In the prototype, Leon looks at the shutter door, giving away the fact that there are enemies behind it. In the final, he will not look at it.

When you open the shutter, the plant 43s will already be up in the prototype. In the final, they get up as the shutter opens.

The prototype lacks the cutscene borders the final has here, and whilst Leon is on the screen in the prototype, he's not in the final.

This background was made brighter in the final.

If you leave this room and come back in, another two plant 43s will spawn in the final. This doesn't happen in the prototype.

In the prototype, the computer monitor does not flash like it does in the final, and the green light is missing. There is no file to collect next to it. The computer can't be used in the prototype at all, whilst in the final, it can be used to turn on the anti B.O.W. sprinklers.

There is also some handgun ammo on the bed, this was removed from the final. The prototype is missing the blue herbs next to the bed which the final has. The prototype has some magnum ammo on the table, this was removed from the final. The cabinet contains shotgun shells in the prototype, and the flamethrower in the final.

Finally, Leon overlaps the sofa in the prototype, this was fixed for the final.

The prototype has a green herb next to the dead scientist, which the final removed.

When you burn the vines away and enter the vent, the prototype has a grid opening animation on it, which seems to be an error since the background had no grid over the vent. The final got rid of the grid.

There is a blue herb on the floor here in the prototype, which the final version removed.

Unforutately, the prototype will freeze if you try to leave this background. And if you wait around for a few seconds, it also freezes. However, there is a way round it...

...if you backtrack to this room later (I came back after killing the giant moth), the room works perfectly in the prototype. In addition to having a plant 43 (which will be dead if you've activated the anti B.O.W. sprinklers), it also has two green herbs, which the final version removed.

I am not sure why the room works if you come back later. It may have something to do using the anti B.O.W. sprinklers, which you can't do until later in the prototype.

When you leave the room, Leon spawns in front of a wall in the prototype. The final fixed the spawn so he's outside the door.

If you go back over to the east area and open the shutter door there, the door at the back was amended slightly for the final. The red light on the computer is misaligned in the prototype, this was fixed for the final.

Strangely the backgrounds match here other than the final being brighter.

In the prototype, if you use the computer, Leon will not put his hand on it like he does in the final version.

Back over at the west area, the prototype is lacking the plant 43 the final has here. It also has two blue herbs, the final changes them to green herbs.

The giant plant on this background lacks any moving vines in the prototype, whilst the final has several.

At the bottom of the ladder, there are again no moving vines on the plant in the prototype, whilst the final has several.

The prototype has a blue and red herb near the door, these were removed from the final. The prototype also has two seemingly misplaced herbs to the left, which are unobtainable -they're overlapping the bottom of the plant.

In the prototype, the door here does not match with the door used on the previous background, the final fixed this. Strangely the lighting effect on the lower right light was removed from the final verison.

In the prototype, a plant 43 drops down here, whilst in the final, it's an evolved licker. The evovled lickers are not in the prototype at all.

This is the only enemy around here in the prototype, whilst in the final, there are two additional envolved lickers lurking around the corner, making three in total.

This background got zoomed in for the final. There's also a green herb here, which the prototype lacks.

This background got zoomed out for the final. It also has two extra green herbs, whilst the prototype has none. The biggest difference is the lack of enemies -the final has two evolved lickers prowling around here, whilst the prototype has nothing.

There is also some graphical glitch with Leon's ankles if you stand in a certain spot in this background, the final fixed this.

The prototype has a small switch next to the shutter door, the final replaces it with a computer terminal. There is a yellow and black pattern around the door in the final, which the prototype doesn't have. Leon's feet also glitch in a certain spot.

This background is in the final, but it is only briefly used when you open the shutter door later on.

These backgrounds had a lot of small changes made to them -there are a lot of pixels around the monitors that were altered later, among other things. The prototype also has a red light on here, which the final lacks. You can interact with it, and I believe it's where you turns the anti-B.O.W. gas on. In the final, you can do this much earlier, in the room with the vines blocking the vent.

The ceiling for this background was amended for the final.

The weapons locker has a white light in the prototype, this was changed to blue for the final. The door frame on the left was also changed.

The weapons locker contains two magnum clips in the prototype. In the final, it contains the magnum parts.

The slide door glitches in the prototype -it overlaps the background when it moves up. This was fixed for the final. There are some other differences, like the rails being changed, and the lighting effect on one of the lockers was moved.

The slide door here is glitched in the prototype too, overlapping the background. Zombies can also overlap things they shouldn't, which was fixed up for the final.

This background has a glitch in the prototype where enemies and items overlap parts of it. Fixed for the final.

These backgrounds have a glitch in the prototype where the slide door and enemies can overlap parts of them. These issues were fixed for the final version.

The final version has a much louder humming noise heard throughout this room than what can be heard in the prototype.

This background was completely changed for the final version.

The angle for this background was changed. Note the overlapping enemies in the prototype.

There is a small glitch here in the prototype -the panel that moves up overlaps the computer. The final fixed this.

The giant moth in this room was moved slightly to the left in the final version.

The monitor doesn't flash in the prototype, but does in the final.

When you use the computer, the English text displayed on it was mostly rewritten for the final version.

The sound effects the computer makes when you enter the user name were made slightly louder for the final. The sound effects for using the different keys were also changed for the final.

When the lights are on, there is some lighting differences between versions.