OK short
I don't think its too short, its a Short, thats all. You could make it longer, with more things happening inside and it would be worth more if you did, but its OK as a short.
Its a familiar theme on NG- there are lots of Tetris experiences and a few 'interaction with the computer' stories, but this one is OK.
It would have been better with backgrounds in the closeups- the boy is against a black background inside the computer but a white bgd in closeup- so its a little confusing.
Obviously it could have sounds in addition to the Tetris music, but its all OK.