If you're that old to live with your dad and live by his rules, what he's trying to say is "focus on studying".
Games aren't very important, you fuck up your school and you fuck up real bad. I was very addicted before but now games are merely something I use my spare time on. You should consider talking to your dad about spare time and school. Don't pussy out, sometimes you gotta handle the talk yourself.
Tips when talking to parents:
-Be understanding, dont fucking flip right away like a spoiled kiddo
-He's doing it for your future, not his. He doesn't want you to end up as a street cleaner or worse, a bum.
-Discuss everything, you might think he's set on his words. Discuss things with him and you might find out a bit and maybe get some cooperation going.
Source: My experience.
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You might think this entire post is pure bullshit, come back to this post in a year.