First thing of note is that the terrain texture in front of the gates originally had arrows indicating the movement of the gates on them. That's pretty cool. This version of the road texture is a little flatter than the final version but does bring back some nostalgia of looking at the old pre-release screens trying to piece everything together. Also we see the level has the original base terrain texture too, which I prefer over the later version which is from the Lab level.
http://imgur.com/f2XYtr0
Next we head down the hill to the start of the power pylons. Of note is that there are no power lines just yet in this version. Also the power pylons are correctly numbered. The first one you see is labeled 13 and it continues on to the power plant where it ends in 1.
http://imgur.com/8Ikyb4P
We head over to the Mayan Ruins and see a lot more detail than we did in Beta 96. Matches the prerelease pictures of the raptor drinking. Also the Quake logo is hidden behind the panel as opposed to the Trespasser T
http://imgur.com/JclroEx
The Raptor Nest area is nonexistent, instead just more forest
http://imgur.com/4PjR74n
The ditches are missing their terrain textures
http://imgur.com/P5XoXOS
But did gain a wrecked Humvee!
http://imgur.com/0r5weWl
Heading to the power plant we notice that the massive hill isn't there and the stream is properly aligned with the one running along the road, just as we expected.
http://imgur.com/x5uvjtO
As we approach the plant we notice that it is missing the well by the side gate and the well out in the forest a ways. Also the moats are missing their gates and the moat is all the same level inside, no dip
http://imgur.com/HVBYl0X
No stairs in case you fall in the ditch.
http://imgur.com/9l9rQmy
Also this pipe heading to the heat exchanger isn't under the walkway, just as it appeared in the Vivo clip
http://imgur.com/eyN5nnK
The Turbine Shed has doors!
http://imgur.com/mDoiO3f
I notice that the cooling tower proportions match my "fixed" version (which I just relocated lol). The textures on this earlier version look a lot better though. Parts of the mesh are still, well, broken. Mainly those damn pipes. Probably gave them a headache

http://imgur.com/IGEKMKY
And the control room foyer as we know it was
http://imgur.com/5Ii1olA
The control room, whose indicator panel is much smaller than Beta 96
http://imgur.com/07iohWJ
The tranformers don't have those stupid fence sections around them
http://imgur.com/URIdKdB
There's no bridge here...
http://imgur.com/Wg1KL2W
However one of the power plant draw bridges is over the second stream here. The first stream has no draw bridge (likely because it's shallow enough to cross just up the road).
http://imgur.com/juvanjz
About where we expect the giant rock mesh to be we instead get this little island actually sculpted into the terrain with a lone pine tree on top.. We should come up with a name for it.
http://imgur.com/nsXuGI6
And the end is horribly unfished with the harbor gate and fence floating in the air and no end puzzle.
http://imgur.com/Ts5kdfa
VERY cool to see this older version. I'm loving it!

EDIT: Ok, it seems the stairs by the drawbridge as well as the other power plant draw bridge are present in the PC Gamer version. That first stream still does not have a drawbridge in that version, as it appears you are supposed to cross it via those little wooden bridges further back. Also it appears the harbor gate is at the correct height, the entire level is about 11 units lower than Beta 96/Demo so the height of the level end would not match up with the height of the Lab level beginning. This also makes the cliffs along the shoreline really shallow compared to the later version. It's also worth noting that there are no dinosaurs present in the level.