a bunch of additional maps (in fact its not even that hard to figure out who made each map after some exploration) complementary to the original doom, bundled together with a price tag, being the most prevalent trend of their design "more enemies OR bigger map = better"...so in lots of them you end up being in a big square fighting a bigger horde of enemies coming at you. hey at least you have the super shotgun to do so...but is it worth it to disregard any interesting progression just to face more enemies?

well yes it was 1994 and people just wanted to kill more demons and the super shotgun is nuts so who am i to judge?