You only get a harpoon and have to kill it in a rickety wooden boat while trying to avoid debris. Gets intense when you get knocked out of the boat and have to swim back with Del Lagos closing in on you.
Oh, a don't forget to shoot the lake before getting on the boat. It makes the battle easier ;)
Marksmanship Rule #1: TAKE YOUR FINGER OFF THE DAMN TRIGGER, MAGGOT!
I tend not to like boss battles anyway, as they're just "shoot it a lot until it finally dies" or "shoot at the big monster's really obvious weak spot".
Having said that, I did quite like Saddler in RE4, and the way you had to find a whole bunch of different ways to take him down initially. Sure, there were a couple of the old "obvious weakspots", but you also needed to use explosive barrels, various cranes, the bridges, and on harder difficulties you could start to run out of methods to take him down. You'd end up thinking "I hope this one keeps him down, because I dunno what I'm going to do next time...."
Kina like Mr. Freeze in Arkham City, only without the pause menu that TELLS you how to take him down.