Ummm people Valve went filed for bankruptcy back in April......goto here and go about 3/4 the way down the page and read that, you can kiss TF2 good bye people.
EDIT: You can also just search for the Headline "Valve Files For Chapter 11"
Are you that much of a n00b not to notice its an april fools joke?
This is also for all other entities like water. actually, ANY entitiy is ignored. Blocked thingsoutta sight by entities won'twork cause the engine will look throught the entity to prepare itself for if you pass it.
Water is actualy the one exception with this rule, the engine will only render whats behind it if its transparent. Other wise it doesnt. If you really want to see what is rendered and what isnt, just download some kind of a wall hack (im not telling you to cheat or anything) and you can see whats rendered and whats not.
Now the hl engine, yes its old and cant do all the flashy stuff like the q3 engine or maybe the unreal engine can do. But do they have the easy of editing? Thats what makes halflife so popular to mod, because its so easy. What made halflife popular? Its mods? No, it redifined the fps genre from the standard find red key here to open red door there. It added more life and more depth, even adding story to it. To switch engines would be to select what esf has currently and press delete.