Time Travel Puzzle Element
Sounds like a great idea. Portal: The Sands Of Time...
Would love to play such a map (and already played the one with world portals mentioned above). Looking forward to your first results...keep it up!
Really? I think your vision is a little bit on the complex side. I see a map with identical rooms parallel from each other with triggers and object outputs mostly.
When you get to finish you project PLEASE make a tutorial! Video or text... anything! 
I think you will need a few custom models to make the chambers seem like they're actually under construction.
[spoiler][SP] Alternate[/spoiler]
Maybe, but I want to trying doing things without custom models, textures, etc. so people won't have to download more stuff along with the map. But I won't abandon the idea having custom stuff made.
My Work
[spoiler]Maps:
Revenge of the Angry Turrets
Capture the Cube [Co-op]
Capture the Cube 2 [Co-op]
TPWEGTH Sample Map
Aperture Aquatic Testing Center
Aperture Aquatic Testing Center 2
Aperture Time Testing Center
ML's Halloween Trick - 1000 downloads!
ML's Halloween Treat
ML's Combination - 1000 downloads!
ML's Jailbreak Labyrinth
ML's Tricky Teamwork [Co-op]
WIP:
"Capture the Cube 3"
Workshop Maps Link: http://steamcommunity.com/profiles/76561198008890579/myworkshopfiles/[/spoiler]
It sounds like a big undertaking to make, but should be fun to play. You could do all kinds of cool stuff with it.
Thanks for over 1,000 downloads: The Cold Shoulder
I have a feeling that its probably going to majorly complex, as there are probably going to be a lot of variables you would need to change. As long as you make it so you can't see yourself walking around, all is simpler.
I have a feeling that its probably going to majorly complex, as there are probably going to be a lot of variables you would need to change. As long as you make it so you can't see yourself walking around, all is simpler.
Take a look at the Showcasing Thread for a 5 picture example of altering the past which affects the present.
My Work
[spoiler]Maps:
Revenge of the Angry Turrets
Capture the Cube [Co-op]
Capture the Cube 2 [Co-op]
TPWEGTH Sample Map
Aperture Aquatic Testing Center
Aperture Aquatic Testing Center 2
Aperture Time Testing Center
ML's Halloween Trick - 1000 downloads!
ML's Halloween Treat
ML's Combination - 1000 downloads!
ML's Jailbreak Labyrinth
ML's Tricky Teamwork [Co-op]
WIP:
"Capture the Cube 3"
Workshop Maps Link: http://steamcommunity.com/profiles/76561198008890579/myworkshopfiles/[/spoiler]
Depends how far into the past/future you are as well. If the time difference is too great it would make sense that GLaDOS would reset or fix the chamber.
It's more like the chamber is somewhat near completion in the past. Remember, this chamber intentionally uses time travel. But the consequences for altering the past can be good, bad, or both.
My Work
[spoiler]Maps:
Revenge of the Angry Turrets
Capture the Cube [Co-op]
Capture the Cube 2 [Co-op]
TPWEGTH Sample Map
Aperture Aquatic Testing Center
Aperture Aquatic Testing Center 2
Aperture Time Testing Center
ML's Halloween Trick - 1000 downloads!
ML's Halloween Treat
ML's Combination - 1000 downloads!
ML's Jailbreak Labyrinth
ML's Tricky Teamwork [Co-op]
WIP:
"Capture the Cube 3"
Workshop Maps Link: http://steamcommunity.com/profiles/76561198008890579/myworkshopfiles/[/spoiler]
What if chell dies in the past?