Since this is PS2, the starting points are random.
First, there are two things you need to know:
The gun - Use the Tactical 12 guage most of the run, if not all.
The trick - The Tactical 12 guage has a very cool trick, not only can you shoot faster, but you also won't have to worry about reloads!
But it's probably hard, right? Wrong!
The trick is easy. You might want to use custom controls for this...
When you switch to your next weapon and then back (or previous weapon and then back to 12 guage), your gun will be reloaded for some reason.
want to use R1 (double shot) the entire time.
So change L2 (normally aim, not needed) to Previous Weapon, and R2 (normally the one shot button for the 12 guage, not needed) to Next Weapon.
Everything else can stay the same.

So, just change the controls..L2 Previous weapon, R2 Next weapon, that's it.
Now, to actually start the level; since this is PS2, it's going to be random...You should restart until you spawn in the pillars.
You also want the gladiator to spawn nearby, either another spawn in the pillar room, or the one up ahead with the ramps and the mini pond thing.
When you *finally* get a spawn in the pillars with him nearby, grab the 12 guage.
Basically, run to him, and press R1 to shoot, then quickly press L2 and R2, not together, but consecutively.
This will make it go to the next weapon and back to the 12 guage, as I explained earlier.
You will be able to quickly shoot again.
It should take 1 or 2 double shots on him to kill him.
Once you are the gladiator, just head towards people, and then quickly press R1, then R2 L2.
It should take two double shots on Leo (the lion, who starts out as gladiotor), one on the weak little aztec guy, two on the other aztec warrior guy, and then three or four on the stone golem...try to avoid him, unless no one else is nearby.
With some practice, and some luck of nearby spawns, you should be able to get under 1 minute.