I'm sure somebody's bound to have thought of this before... In fact, I'm sure I've read of somebody else suggesting this in the past... I just want to know if it's possible, or better yet, if it's been brought to fruition.
So many parts of HL2 would be more fun playing as a TF2 character... Imagine going through Nova Prospekt as an engineer, or Ravenholm as a pyro, or Follow Freeman as a soldier. I bet each class would be a unique experience for the game, but I guess that trying to splice these two games together would require tons upon tons of balancing and tweaking of the weapons and all. Having working sentries, teleporters, spy knife/cloak and pyro fire...
It's a fun idea, but I guess it's probably no more than that, eh?
Oh god, something just hit me: Now imagine playing with the Synergy mod and your friend(s) picked different classes.