Fake water
this has been done. i can't remember the level exactly. but you would place a portal under the water in one little "square" area, and another NOT in water in another square area.. and the other area would flood with water there by floating a table in that area.
vague i know. but i'm tired. or something, but i have seen it done.
Sometimes I get the idea mapping for any Source-game is slightly like Murphy's law: if you think of it, it has been done before. There goes another of my wannabe-brilliant, wannabe-original ideas...
Doesn't change anything to the fact that it would give some cool puzzles, though hard to implement.
"Duct Tape is the answer."
Wait, wait...
I never said that we could make portals in water. Of course we can technically, but visually it causes bugs and technically it would demand thinking do do water transver from silo to silo, an idea I would immediatly exclude.
The point of the fake water is to save visual resources, and in game, it would be playing the same role as goo but with dangerousness toggleable with a superbutton for example. Coupled with a cube floater for example. Never meant to put portals in water.
The gameplay advantage is that it is immeadiatly identifiable dangerous by the player with electricial arcs and zap sounds, unlike a metal floor with wires on it. You don't need to be a genius to know that electricity and water is not good.
Author of Minecraft mods (MAtmos, Minaptics, NoteSlider) and Garry's Mod addons (Gunstrumental, SharpeYe, GarryWare, DepthHUD).