Spoiler warning, I guess.
Okay, I'm going to quote two moments in video games that actually made me cry.
First was the dialogue between Irenicus and Elesime in Baldur's Gate 2. Okay, so it was more like weak sobbing because poor acting and being to far away to see expressions broke the immersion a bit, but I did shed a few tears at that moment. It was a very well written tragedy.
The other was the death of Eli Vance in HL2e2. I'm secure enough in my masculinity to admit to crying at that moment. The players involved are all really well characterized and the acting was really good and that fact that Gordon is a unstopable badass caught off-guard and forced to watch helplessly added to the impact of it, because it made me fell like it was all my fault.