Paranoiac

improves HEAVILY over Paranoid, while still keeping the very first episode of it, some of the levels are shorter than the ones in Paranoid, which is good, plus three new weapons and a few new enemies show up too. the last episode is a strange one, putting in Doom monsters in a Half-Life-themed mod for about two levels. Very long-winded, but worth the playthrough.

settings are done well, from Black Mesa to Xen itself, although not everything is perfect. the Gargantua doesn't seem to have a mass value so hitting him with an RPG (or even the headcrabs with that one that you are supposed to fry with electricity) makes him go flying. also some of the moving platforms in the Xen episode don't seem to work properly, in other words, I seem to slide off of them if I don't keep up, and a few corridors seem to have a wind effect when they really shouldn't.

Level design is wonderful thanks to the extensive use of 3D Models and other advanced GZDoom techniques such as slopes and various other effects, you assume the role of an agent who's mission is to upload a virus to Black Mesa databanks, your progress is complicated by different encounters, zombies, Xen creatures and HECU forces, the levels are connected together so you may have to revisit locations to complete objectives.

A fantastic looking mod however it suffers from few balance issues, there's too many enemies on the first levels and very little ammunition, I ran out of ammo several times before doing any progress, Vortigaunts and HECUs are tough as you would expect them to be, throwing grenades at you occasionally, those were the reason I repeated the level over 4 times, I had to use the save game option eventually, It wasn't until later in the game when things started to pick up as I gained more weapons and ammo, I was little bit disappointed you couldn't recreate some of the weapons like Tau Cannon, Grenades.

The pace is slower compared to other Doom mods so you're going to have to take your time to explore levels looking for your objective, the mod does a good job at directing players to their next objectives via walkie-talkie pickups, There's a bunch of secrets here and there, most of the time they are hidden in vents, I liked the level where you can torture Xen specimens held by scientists lol.

The last fight on the first episode vs Gargantua, I'm not sure if this is the intended behavior but this particular enemy has a very low Mass value, meaning the Boss keeps bouncing around the field as you fight it.

Overall it felt like a nice break from regular Doom maps, it may be tough on the first level but as soon as you move on to next level and gain access to more weapons and ammo things get a little bit more interesting.

EDIT : I just noticed there's 3 more episodes, weird the mod doesn't take you to next chapter after you're done with the first one, going to give them a shot.