http://forums.spiralknights.com/en/node/1526 <--- Second post tl;dr basically says: Yes, they do every type of damage
In game, hit help -> clockworks <---- Basically implies monsters do no/little normal damage.
Just need to know this so I can effectively decide on what 5* equips to get.
Alright. I guess the best thing to do is have an even mix of every defense..
You basically want Normal + whatever depending on the stratum theme. I'm not really sure how to handle the fire/freeze/poison themed stratums though. Well aside from swear a lot during the freeze ones.
if in doubt, go by the color of the charge up animation the monster does -- if it's red, it's 100% normal damage regardless of tier
Some attacks are still normal. Robot swipes, Gremlin hammers and Wolver bites all do normal damage. Special attacks like bullets and Skelly swipes are exclusively a specific damage type. Basically normal damage still comes from ordinary attack types that never saw a secondary damage type in T2.