If you don't use the C&D, You're the worst player in existence.
I tried the tutorial for the lulz, and it's pretty good for the newcomers. I just tried offline mode, and its awesome.
For some odd reason I think the engineer update is valve's surprise.
No it's not, it's portal 2 themed
if you don't use the C&D for what it can do then you're being an idiot
Spies are really just there. The game doesn't need them. They're sort of like... a filler classes. Like heavies. For when you're new and/or you want easy kills.