Ok. I know little about it (now) since it has been so long since I've seen it, but here is what I DO know:
1. Must have been made prior to about 1999-2000, because that's around when I saw it. Most likely in the early to mid 90s (possibly even late 80s)
2. The artwork is more similar to say, Akira, Demon City Shinjuku, X, etc. Not of the cutesy, Sailor Moon variety by any means
3. The premise vaguely seemed to me to have something to do with a protagonist mercenary or militant character of some sort that is trying to get into some kind of compound, which is heavily guarded. He's apart of some rebel force or something that's doing gun battle and hand combat with the enemy forces... possibly in a snowy, mountainous scenario of some sort. I definitely remember some of the enemy vehicles and droid machines blowing up on cliffs and a snowy environment. This protagonist might even have barely escaped death by surviving a big blast or something. I can't remember!
There are some other characters that are trying to get in there too to find something and stumble upon some kind of alien technology that allows those who enter to see surreal images or whatever is in their dreams... or something. I remember that when upon entering, they first don't really see anything but then start seeing fantastical manifestations like T-rex and other weird things.
4. I'm pretty sure one of the antagonists (bad guys) is a kid with a giant head or bulging brain, that's hooked up to a computer or telekinetically uses computers or something. Whatever it is, he talks like walking Thesaurus and is all uber-smart. I remember he's in some sort of capsule or small room, dimly lit with a faint green tint in it. It really doesn't show him outside of those surroundings. That part could be off. I think he might work or be the leader of some corporation or faction that has this scientific team investigating their find (the alien ruins or whatever).
5. Most likely it is alien of some kind, so that it would fit the overall sci-fi / post-apocalyptic, futuristic feel.
AND no... it is not Akira, Ghost in the Shell, Metropolis. Those stories have none of these details in them! That's the common response I get (eh, novices... )
I know some of you have seen it and I'm sure some of my details or memories of them are a bit ambiguous... or have been altered over time. Who knows, I could be WAY off.
I MUST know the name because it is driving me absolutely insane and NOTHING on the internet is remotely helpful!

Sounds like,

Spriggan

-view trailer-

DUUUUUUUUDE!! You nailed it!! Oh man, a huge weight has been lifted. You don't understand. I was losing sleep and No one at the local comic shops or anything knew which one I was talking about! Oh man... you're a lifesaver. You don't even know. I was losing sleep over this because I seldom forget names of things and such. Awesome!! Thanks again!!