What expansions are included in this from GOG.com?

All the extra's don't know what really you can find it on the web. ;)

The atomic edition features one additional episode, entitled "The Hive". There are therefore four episodes total, the three original episodes of the game and the extra fourth episode. This fourth episode introduces one new weapon, the Microwave Expander.

The edition sold by gog.com is the final patched version 1.5. the atomic edition includes the episode you could get in the plutonium pak expansion that patched the game to 1.4

You can get the official download from 3D Realms as well I believe.

Is this the whole game? I reached a deadend in the abyss and found a video on youtube to help. The cave entrance displayed in the video (directly below shrink ray cave), is not present in the version I'm playing. Everything cool up to this point, playing in XP.
I downloaded the game 2 weeks ago from this site.

Here's the vid [ http://www.youtube.com/watch?v=tCB4_2cxTqo ]
I've got secrets 4 and 5. Late in the vid he leaves the dancin babe and takes off down the acid and flies into the shrink ray cave. He then drops out and down to a cave directly below.
I do not have that cave nor the other two directly across from the shrink ray cave?
I'm just killin time till FOREVER gets here but I've spent two nigths trying to get on with it .
Thanks for anything :-)

I really wish the other expansions could be included here, including the duke!zone level sets.

That cave opens up after an earthquake-type event. I forget what actually triggers it, but I think you need to be in the cave ACROSS from where the shrink rays are coming from ( basically, follow the shrink rays and see where they're shooting to, and go there). There's a cave there where you are supposed to get hit by the shrink ray so you can get through a tiny passage. I believe as you move through that area there is an earthquake that will open up the cave below the shrink ray emitter.

Does anyone else remember exactly what triggers this earthquake?

That was easy enough I guess. Went to the 3D realms walkthrough and found out you gotta look through the window to bring down the wall while in the get shrunk puzzle room. Did it the first time through, replayed from the save without looking out the window and left myself in a canyon of lava with no exit ... :-)