I liked it. Nice punchline which I wasn't expecting.
The music was perfect and I liked the balance with the ambient audio of the keyboard tapping. It was very clever really as you had to put the idea of what was happening on the subjects computer screen into the viewers head without showing it.
This again shows the power and importance of music and sound. The headphones were essential to the plot as tehy explain why we hear nothing of the SFX from the game.
Of course that music and sound together with the shots of someone franically tapping away at the keyboard/mouse could equally well have been a high tech thriller so making sure that the domestic surroundings were visible and having the word "Gamer" in the title was also necessary to ensure that the viewer got the right idea.
If all of this was intentional on your part, then fantastic - you clearly know how to build a scenario.
If it was subconsious - equally fantastic - you obviously have a talent.
If it was all luck rather than judgement - then also fantastic- you've just learnt something! (As I did, just putting these thoughts down)
Almost certainly it was a tad long, with several shots basically being repeats of earlier ones. Repeat angles are OK if something different is happening, ie if it's during a conversation so different lines are being spoken, or the plot has developed in some other way such that the repeat shot makes sense, but in a montage where just the same action is being repeated, be very careful of oversuse.
I liked a lot of teh shots, my ain disappointment being that the shot which begins at 0:06 duidn't change focus to the gamer's left hand when it came into play at around 0:09. But that may well simply have been an artistic decision you took.