Multiple env_projectedtextures
Simple question. Has anyone figured out what exactly you have to do to allow more than one env_projectedtextures to be ON at the same time? I am making a coop "horror" map and i want to give both players flashlights but because of that limitation im propably gonna have to use either impulse 100 (Which is bad because the impulse 100 flashlight is only visible client side) or im gonna have to use.......light_dynamic 
. Please god someone help me because i do not want to use light_dynamic.
Not possible in any Source game except Garry's Mod; it's hard-coded into the engine.
I wonder if you switched between them enough times per second, if it would look like both are on at the same time. Maybe you can get a flicker patern that made it look like one was flickering off while the other was flickering on. I could also imagine a lot of cooperative gameplay potential in only one player having the flashlight. Limitations are the playground for innovation.
Don't know if Source can trigger things that quickly; probably only to a few decimal places, not enough so that it wouldn't induce epileptic episodes. Regardless, it would still most likely cause a lot of lag.
It's possible... by recompiling the source engine to allow it. Good luck getting WS players to install your sourcemod, though. Plus it causes buttloads of lag iirc. Not worth it.
I remember one map on the workshop that had 2 rooms, and tried to fake it by flicking a projected texture on when you entered the room and turning it off when you left. Problem is, since the rooms were part of the same puzzle, you would walk through a portal into a dark room and end up in a brightly-lit room because the light turned on. It was super annoying and I really hated it, shame because the rest of the details were gold.
I guess you have to just settle for 1 projtexture 
I hope you can make it work out!
It's not possible, as mentioned above. If you know some coding you can try to alter that, check out this However it is like that because a reason, think about the memory consumption and the damage in performance in some low-end pcs.
You can use poweful light_spots in addition to lowering the lightmap scale on some floors and wall textures around it. You'll get some good shadowing effect.
useful tools and stuff here on TWP 
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For the means of a flashlight, though, wouldn't that be static, unless you wanted to place a bunch of differently named lights in every possible direction with trigger_looks everywhere. Of course that would also cause your CPU to create a rip in spacetime.
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If you want nice shadows, but not an actual dynamic light, it's possible. You just need a light_spot with the right settings - it's done in many places in Portal Stories: Mel. I, however, don't know the settings.
Lpfreaky and tmast98 would, though.
For the means of a flashlight, though, wouldn't that be static, unless you wanted to place a bunch of differently named lights in every possible direction with trigger_looks everywhere. Of course that would also cause your CPU to create a rip in spacetime.
Ye, I meant static shadows, not dynamic... that's the con, however, you can get some spooky shadows for some places even though they're static ones, plus the actual dynamic shadows with the env_projectedtexture ...
useful tools and stuff here on TWP [spoiler]
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Why not have 1 flashlight, but make the sharing of it part of the puzzle ?... you could have specific points where they could swap the light through round-mesh-hole grates if the players are in separated rooms etc... Working with the limitation and adapting your idea is likely the better solution than trying to figure out how to have two env_projectedtextures ....
Just a thought... it is a co-op map anyway.... ..