As a pyro you should use your flame thrower to jet pack around and gain speed. While doing this you should strafe left and right and burn heavies.
You can also use the I.C to set people on fire and burn them with the flame thrower, then finish them off with the shotgun or crowbar.
The heavy isn't fat, therefore the game sucks >:(
Eh, personally i prefer the original TF2 Graphics over these
This mod has been around longer than TF2 and as Marcem said these models are based off the quake ones.