There could be a lot of things going on. Hormones for sure but exercise is great for that. He could be having a social issue at school. Does/did he talk to you about friends/school issues?
Do you do things with him like ride bikes/roller blade? If not, I'd grab a bike and say "Hey kid, this is the deal, we ride, no questions, let's go". It's hard to have a bad attitude on a bike and maybe he needs one on one time with you that is just fun. Try that first.
Then, ask him if he'd like to actually make up a video game.
If this is what he is interested in ( and what ten year old boy is not?) then get involved. Play a game with him, get him to teach you one, you'll survive. Then, if he is that darned smart suggest he start working on his own game. You can go to the library and get books on gaming. You can even find people who do this for a living and take a "field trip" to see them. One very bright boy of 13 I know, is reading about artificial intelligence and is building a robot. There are robotics classes all over town and robotics clubs. Whateve he is interested in, feed the need and get involved. Don't be a typical parent and close the door while he plays alone, get in there and support his interest. You don't have to turn into a gaming nerd, just be supportive. But do NOT let this interfere with family time/exercise/ balance is key.
Also, do you guys eat together each night? DO IT. This is crucial. I'd suggest a family board game each night as well, but something tactical like Risk or take turns challenging each other to chess, if you can't play LEARN. Most kids who are great at video games are masterful chess players as they are problem solving constantly in gaming.
You have a smart kid here with a lot of love inside. Just find a way to involve yourself in his world and him in yours.
Does he cook yet? If not it's high time he learns. Lots of kids are craving responsibility at this age but they don't get it. Institute a family cooking night where each person contributes, even if he is making the salad, he is contributing and the reward will be huge when everyone says "great salad!" Some of this stuff is so simple but we live in a world that goes by at warp speed. Slow down, ride a bike, cook a meal with him and play a video game with him. You will be surprised and you will have your boy back.