The reason I bought Orange Box is 80% for Portal. 10% TF2, 10% Ep1&2. Now after playing TF2 and Ep1, I have to recalibrate my percentages. But Portal is still well over 50%.
For that portion I did the same thing I did to break the glass. Use the rocket launcher to break the cube tube. I believe that this is the 'correct' way to do it. 10/10 game for me. I absolutely LOVED this game. Yes it was short, but damn FUN. Reminded me a lot of ICO.