the first half of the new doom campaign is... mostly fine. looks great, has a banging soundtrack and is generally a step-up in difficulty compared to base doom (around PE's level) which is my speed. im not a fan of the plasma gun replacement though, it's way too situational since it damages you and drains ammo ridiculously fast.
the new enemies are also mostly fine, though the level design uses them in some dickish ways. E1M6 The Coiled City is filled with the Goat Demon guys who throw area-of-denial fireballs, with a radius i cannot figure out for the life of me. easily the least fun map of the bunch on UV, nothing but them, the new flamethrower mentioned above, tiny walkways and constant ammo/health starvation.
they also erm, "borrowed" the plasma marines from Scythe 2. as in, they're the exact same enemy. in fact, the secret level Ash Mill is heavily inspired by that WAD's Mr. X introduction of them. they feel very out of place compared to the others.
idk, aside from one broken area, Legacy Of Rust is decent by base Doom standards but nothing show-stopping yet. one more episode to go.
edit: this pack has the weirdest difficulty curve. E2M1 and M2 are stressful chit-damage management tests, while M3-M4 are slow, typical crawls with plenty of ammo. odd.