Beating the boss in Mansion of Madness involves simply side-stepping in
one direction while aiming up and turning. The closer Cortez is to the
fountain, the greater the chance it is to avoid being swiped. When the
boss is about to die, step back and fire the last shots to avoid the
final death blow.

Beating the boss in What Lies Beneath involves simply using the Ghost
Gun and knowing where to stand. Locate a rock that shields Cortez's legs
while allowing him to fire back unimpeded. The fire attack from the boss
has to drop to the floor before moving forward; this simple rock
protects the player from most of the fire breath damage. A melee attack
will destroy the bats and allow the Ghost Gun to damage the tank.