Ok, so I noticed that you had a question in my GTA senario. Essentially, My car was a separate class from my player and these vehicles and players extend a scrollable class. This is so if any of the actors in the scrollable class are within a certain bounds, I scroll the world. So if my player is colliding with the car, then it checks for a key. If that key is pressed, then the car has a boolean "is driving" or something like that, and if that is true, then it will move and my player no longer rendered. When I exit the car, I simply set the location of the player to the car and move it right 10 pixels or so. You may want to develope a system that places the player where there are no objects in the way. But basically this is how I did it and I hope it helps!

@dufus15 its all about realism. I am creating another pool game using the Slick2d library in intellij and this time I am focusing on more realistic and accurate physics. I am incorporating a rolling effect for the balls. Visit 8 ball pool on miniclip.com and that is basically the type of pool game i am trying to create.

@danpost yes, I forgot to remove the space bar feature. I also said I would create a new wall collision system because the one now is temporary. This is a very basic version of the game. I line the walls in vectors and at each intersection, I will invert the angle of the vectors normal. This will provide much more accurate collisions and will fix the getting stuck in the wall. And for the repeating sound, I need to move where the sound is actually played to get rid of the constant detection.

A smoother scroll system would be effective, and again, I made a 2d minecraft in intellij with my sprite sheet and it is amazing how much better it looks.

I made a 2d sprite sheet of this same character that I made that looks really nice. I could send it to you and you could just make a simple animation class that takes sprite sheets and crops each picture. If made one too If you want a look

I noticed a few small things; the dice at the top I assume are based on the arrow keys, not the centripitol, i think, force, so before you start moving, the dice fly to the side pressing the arrow keys, but that can easily be fixed by not doing it as long as your velocity is == 0. Also, The dice fell from the top when I was hit, so I dont know if it was supposed to do that, but if it was, thats pretty awesome. I was also curious if the opponent is more of a AI or just follows a defined path. AI's would probably steer back on the path if you knock them around, or they might try to cut you off, or take corners a bit different.