This is a rather interesting cheat. It will kill you so if haven't saved just before you do this well, it'll be bad. Anyways, when your at the lake stand at the end of the pier (The one next to the boat), and raise your gun (any gun works.) Now simply shoot the lake water five or so times and Del Lago will suddenly pop out of the lake and eat you.

When you have the striker out press B to aim and then quickly go into your attache case (note: you must do this immediately after you press B before the weapon is ready to fire) and switch to a different weapon. If you switch back it will stop. This will make you run, knife, and reload faster.