Pretty good

Re: your comments:
- I did not see any problem with darkness. I have told you about contrast&brightness calibration before.
- Blue gel jump height is very consistent, but the first jump is always shorter. And it depends whether you jump from the gel or onto the gel.
- Turret randomness (and more relevantly, physics engine randomness) is a known problem with this map, sadly. Much work has been poured to it, fruitlessly.
- The vents don't work well. Known problem with FGEmod.
- I don't know what you mean by misleading blue cube. Everything was as it should.

At the end of 2nd demo: I'm not convinced that you were stuck at all.

It is possible to pull the cube through, but it is obviously not a part of the intended solution. (2/2)

1st demo: I totally love your inane solutions that are so different than what I had in my mind. Even GLaDOS snarked at them. I forgot I added those lines. Sadly some of them worked. I'm kind of divided whether my solution was cooler. The turret-sucker was not there just for decoration, you know. The role of the turret(s) was to teach you how it works. Slow thing approaches, but speedy thing goes in. (1/2)

The last demo showcases exactly what I find bad about this map:

- first area is a bit too dark and the drop is hard to portal into (the gap)
- inconsistent jump height from blue gel.
- after going down the lift, the turret sometimes gets a perfect angle on me and can kill me if I don't use portals.
- after dealing with the turret, there's this turret which is not optimally placed for the vent thing to make sense : http://gtm.steamproxy.vip/profiles/76561197985463720/screenshot/314494866255189573
- misleading blue cube at the end, although this adds to dificulty (where I gave up in the second demo).

All in all it's very well thought out map, despite the problems that could be chiseled out with Hammer (the pneumatic diversity vent bit especially) so I still thumbed it up, but not exactly my fav.

First try, where I stopped 2 days ago [www.dropbox.com]
2nd try, thought I was a smartass for bringing the companion cube [www.dropbox.com]

Beginning to end 3rd try [www.dropbox.com]

I had to bring the companion cube after all!

Map updated utilizing most of the feedback I have received.

Ah, yeah, that explains it. The number of gels is what's killing your framerate then.

U7300, G210M here. Laptops are quite different compared to gaming computers.

Yeah, the sphere and cube is what I meant. I'd suggest the route back opens an angled panel with that last button that opens the door to the tube. Turn off antlines and signage on the panel. Maybe put 2 strip lights by the panel so it even more obvious once the person comes back to the beginning. Of course also leave portalable surfaces in the tunnel so that if they do go down even after doing it correctly then they can just portal back up.

Oh, about the framerate issues on my last one. I have none at all. I stay at 60fps no matter what map I play. I have an i5 CPU, GTX 660 GPU. 16GB ram, Win8, and video settings maxed out. You probably need some upgrades as mine are far from being a high-end machine.

I hope this helps or gives you your own ideas on a way to fix that.

The diagonal glass barriers are indeed a bit glitchy: I used a puzzlemaker glitch to make them. It looks better in the underground part (at distance) than in the long corridor.
Take both cubes..? I hope you mean the sphere and the cube. You're not supposed to be able to get the other cube (once it is fulfilled its purpose) . But yeah, if you forget to take one, you need to redo all but the middle of the puzzle, which does take some time. When would you suggest that the route opens? Originally I had the glass between the pit and the one-cube-button-corner open up, but I wanted to use the cool vent pipe system so I changed it.
Unfortunately I cannot affect the behavior of those tubes, slowing them down or otherwise. Beyond my expertise... Let's hope BEEMOD 2 will have better tubes.

I liked this one better for sure. About a medium in difficulty. The angled glass panels are glitchy looking as if you used that bug in the pti where they are on an angle, but the framing is all weirded out. You can screw yourself at the end if you don't take both cubes with you... which I almost forgot to take the sphere and would have had to go all the way through it again. Would be nice if there's was a way around that. I've always made an alternate route open up for cases like that. Just have a simple tunnel from the first room drop down into the last room where you get the cube and sphere. Have the door to access the tunnel opened by the cube button by the gel. Also, if you could slow the tube going back down so you could see anything that would be cool. I know there's no way to do that directly in the mods, but you could open it in hammer. Anyway, overall pretty fun map and good use of the various mods.

I'm not aware that I avoided using any puzzle elements on this map. Maybe it looks like that because I try to explore each corner when I feel I'm not seeing the whole picture yet. Before I press a button I like to know why I'm pressing it. The diagonal glass was too odd looking, I just had to go up there. The narrow passage scared me, all the layers - laser field, grating, piston platforms, turrets - made it hard for me to digest and when I'm not sure what's going on I hesitate. There were a lot of turrets but I only remember killing one of them actively, the others were removed without me knowing, giving me the feeling like I passively wander the map. I'm undecided about the first two momentum parts, a lot of people are probably unaware about these mechanics, the part with the cube momentum was really nice though.

Thanks for playing and for the demos, toncica. I find your playing style odd. In general (I've observed this before), you seem to avoid the puzzle elements such as buttons as long as possible, trying them sort of as a last resort only.
What happened with that one turret was really weird though. It was stuck in the edge of a turned angled-panel as done to it by physics randomness. What can I do to help it?
You noticed some weird air currents as well... Heh. Don't know if I can help that either within the limits of puzzle elements I have been given... But it was harmless.
You also found an unintended solution to the cube-fling problem (in addition to the correct one, which you used later).
Any comments on the map other than a bug report? Opinions? If it isn't too much to ask.

One of the turrets was stuck and killed me multiple times. I had to go notarget. https://dl.dropboxusercontent.com/u/16159596/momentum_toncica.zip

Thanks Felix Griffin. In my first attempt I tried the mdl files (in props_bts) referred to by vactube*.vmf . That wasn't enough... So I added everything that has "tube" or "pipe" in it, except for the vmf/vmx files and files in palette/ .

The files you need are in models/props_bts/vactubes something, I don't remember the exact names. Those should be the only ones necessary.

Yeah, that is right. I added all files that somehow were related to pipes. I wonder how to know which files are redundant...

I suppose it's fine now: http://gtm.steamproxy.vip/profiles/76561198053334196/screenshot/595879971526067098

Lamentations.
EDIT: Updated again, this time adding even more possibly relevant files into the bsp. Assuming I did it right.

Just redownloaded the map after your post and it looks the same.

toncica, looks like you are right. My friend didn't see it necessary to mention that problem to me (he thought it belongs there). Heh. Let's see what I must bspzip.
I updated the map now. Unfortunately I have no way of testing myself whether it includes all the necessary models...

Hi toncica! That is odd. It worked nicely for a friend of mine who had no mods installed...

I've aborted my run right at the start because I'm not sure if this is just a cosmetic problem or if the map won't work properly for me: http://gtm.steamproxy.vip/profiles/76561198053334196/screenshot/595879971517452404
The only mod I have installed is the Stylemod.