for those of you worried about the demo ruining the game...don't.
it is just enough (maybe not enough at all) to give you a feel without disclosing any of the bits that will most certainly make this title remind many of us of the classic iteration. i was actually reassured after reading the write-up (of the demo) in Rock, Paper, Shotgun.
Some Things You Should Know About The XCOM Demo | Rock, Paper, Shotgun