Some offscreen gameplay:
Light my fire: http://www.youtube.com/watch?v=QjfWQxGJlkY
Scanning: http://www.youtube.com/watch?v=iRbQMuFAHEo
Infected: http://www.youtube.com/watch?v=thzzjGiYvAY
The creepy stairs: http://www.youtube.com/watch?v=qEiAmBAFbyg
The persistent zombie: http://www.youtube.com/watch?v=v4lF0KQNdMg
Reunion: http://www.youtube.com/watch?v=6gXMbqzjQ0M