Looks very nice, thought about releasing it for Ouya as primary plattform? Basing your controls on a gamepad might give you more possibilities on how to make input or combat system.

Look at the code, its exactly the same as before, just that the Thread is started from your other class. I edited it because (without knowing your architecture), it just felt a little more right to me

You have to pass your Runnable to the Thread as parameter

Thread thread = new Thread(this);

and start it just like this

gameWindow.startThread();

without:

gameWindow.run();

EDIT:
better do like this
instead of


put

I know it's easy, but it's very OOP, that's why I was wondering...

How did you get along with Swing when your Java skills are that basic?
Just wondering

Who of us wouldn't like to make a living on making games?
I guess it's possible, but quite difficult and alot of work. I can only tell you about my own experience. I am a student and I have developed a little game that's on the android market. It's a casual game, programmed with rough edges and the graphics are not the best. It has room for improvement but still a nice game I guess. I don't know what impact quality has on download rates. It's a free game with ads on it. I think the most important thing is marketing. There are tons of games on the play store, so you have to advertise your game one way or the other. I added my game to some android gaming sites and did some forum posts. What surprised me is that I have constant download rates per month since I released it 12 months ago.
So from my experience I'd say you have to make good games and even better marketing