Hiya!
Most people seem to agree on a few extreme cases of adversarial DMing but not so much on the rest. So help me out. How do you define adversarial DMing?
For me, "Adversarial DM'ing" is the DM specifically trying to DM his/her game as "uncaringly as possible"...in terms of PC survival or detriment, and not hiding his/her emotions when highly unusual dice/situations come up...even at the expense of a PC.
I would classify myself as "mostly adversarial" in this regards; maybe 90/10. I don't
like to see PC's die, and sometimes it honestly pains me to have to roll the damage dice and say "...oh man... sorry... 19 points of damage; Freelick, the Franetic of Glossamere, is impaled, and dies". But I'm not going to downgrade that damage to only 9 points just so Freelick lives. A non-Adversarial DM would probably do that, favouring the PC because of a "fluke dice roll".
Adversarial means I do 'try my darnedest' to "kill the PC's"...but only insofar as I am playing to role of the bad guy; the
bad guy WANTS to see the PC dead. I may even play up the 'glee' of when the bad guy hits/hurts the PC for effect (e.g., "Ok, his turn... [rolls dice, gets a 19]... HA! Take that, Glascia! Straight to the sternum! You're going down, Fighter!"). But...and this is key... my PLAYERS understand that I'm NOT CHEATING and
I am NOT TRYING TO KILL THEIR PC!
Usually I may smirk when something bad befalls the PC's, but that's for added effect. It gets the Players more emotionally invested in the situation because I am, effectively, "everything". To relate to real life...it's like when you go to wash your car in the drive way. You walk outside, around the corner of the house to turn on the water...and step in dog poo. You clean that off, then get the bucket, sponge and rag, and hose. You turn on the water and discover the hose nozzle is busted. Wonderful! You take it off...and cut your hand in the process. Band-Aid it, then start washing. You start to scrub the car only to realise the soap you are using stings your new cut like a mother! You put on a rubber glove...and get back to it. Surprise! It has a hole in it. ... ... So, in this 'real life' scenario, I, the DM, am the one rolling the dice behind the screen for all the fumbles you are making ("Perception...you failed? Huh... you step in dog poo"..."Right, you think you have everything; make a Cleanliness check to see how you do. Another fumble? LOL! ...Your nozzle is broken and you cut your finger for 1 damage"... "That's two fails in a row...time to roll on the Murphy's Law table...", etc). Sometimes life is darkly funny...and if you were the DM watching such dark humour unfold unexpectedly, well, enjoy it! It makes all the times when the PC's plan is smooth as butter and they kick azz that much more special.
So, long story short, "Adversarial DM'ing" is when the DM specifically doesn't care about your PC's success or failure...and at the same time gets enjoyment as a Player does...but from the perspective of the monsters/environment...as the game unfolds and dice are rolled. Players rejoice and high five when the fighter one-shots the Orc Chieften...so why should they get all the excitement when the Dice Gods smile on them? If a DM rolls well for something that tosses a spanner right into the PC's plans...he smiles, lets out a chuckle, and may even say "HA! Take that!". It's enjoyment at fluke rolls and surprising turns that can happen in an RPG, plain and simple.
Now, a DM that specifically sets PC's up for failure, knowing the most likely outcome...? That's not Adversarial DM'ing. That's just being a Richard!
^_^
Paul L. Ming