Hey Blue,
I like where you are going with this. The tank looks cool close in - so zoomed out a bit will make it look even better.
How to zoom out?
Look up the mod Kyatrics signature - it has a wealth of information and is pretty much my first stop when i get stuck.
How to improve the physics? (rotates too slowly)
do you mean when the tank comes over a hill? I actually thought it looked pretty good.
How does the game show on your screen? On my screen
Same for me.
How is the performance on your computer?
Great! :)
How you think I should improve the game?
Zoomed out a lot more for a start, thats about all i can comment on at this point. Looking forward to you adding more though!