Portal - Tutorial, walkthrough, instructions.
00:00 chapter 0
01:40 chapter 1
02:30 chapter 2
03:25 chapter 3
03:55 chapter 4
04:52 chapter 5
06:10 chapter 6
06:45 chapter 7
07:50 chapter 8
08:55 chapter 9
09:40 chapter 10
10:47 chapter 11
12:25 chapter 12
13:40 chapter 13
15:05 chapter 14
17:00 chapter 15
20:30 chapter 16
23:30 chapter 17
27:00 chapter 18
31:25 chapter 19
33:30 escape
46:10 Boss fight