First of all, I must say I had a lot of fun playing GunBlood. Feel free to find the game here:
First, the game play is very simple, yet elegant. You need to keep your mouse by your ammo in the lower left, and when the words say fight, shoot your opponent before they shoot you. Headshot is instant death, while a shot in the foot would only take 1 point off. If you manage to get the first hit, make sure you keep firing, as the computer cannot fire back. The game is difficult as the computer can and will give you a headshot at random. Even if you both headshot each other, you lose.
And to the cheats? oh yes. Here you are:
nohit =invincibility
fastfire=fire faster
pointer=red dot sight
moreammo=unlimited ammo