Magicka: Grimnir's Laboratory

Summary pulled directly from Steam - Some text may only be applicable to Steam platform

Deep under Castle Aldrheim lies Grimnir’s laboratory, a secret long kept from all Wizards of the order. A crazy-random happenstance during recent “cellar activity” has caused the wizards to discover this long lost lab and all its horrors!
Fight against 16 waves of monstrous foes on an all new map. Experience a new twist on the traditional challenge mode with elemental alters that dictate what spells and elements can be used. Three new doctors, in oddly familiar robes, have come to your aid in defeating the hordes. Will you and your friends be able to survive Grimnir’s horrors?

Key Features:

A new challenge against 16 waves of monstrous enemies
Employ new tactics and cooperation to survive the special mechanics
Elemental altars control spell usage
New enemies: Grimnir’s long forgotten experiments
3 new robes give you a unique experience of playing a certified Doctor
Dr. Quake: Clad in armor and armed with two lightning dispensing gloves. Just make sure to stay away from lightning yourself
Dr. Terrible: A lab coat with good protection from the elements, a Death ray and a Trans-matter staff. Everything one needs for a doctorate
Which Dr.: Sporting a brown blazer, a trendy scarf and a nice red Fez, the latest in fashion. With a Sonic Tuning Fork and a Magickal piece of paper, this wizard is fully prepared for any time travel