I have played through the pack and this is really among the best, if not the best. What First Day lacked, is now overrepresented: Variety in themes and design approaches is one of the striking features of the pack. If you thought, JazzyB could only create convincing human bases, you will learn that he can also create convincing decayed ruins, high mountain peaks (one of my favorites!) and Skaarj bases. Especially the last one let my jaw drop several times, something Zephon could not achieve even once. It is obvious that the last Skaarj area is influenced by the likes of Zephon, even the ending is similar (youve got destroy an energy core that is guarded by a WarLord), but JazzyB surpasses his predecessors in every aspect which probably comes down to careful planning. The maps are interlinked, making you visit places you could only see in a previous map, by the translator messages you feel like you really tear down this place and disrupt the Skaarj activities, most of the rooms serve a clear purpose (the Hatching area was probably the coolest), there is as few backtracking involved as possible (you just gotta remember everything, not always easy ^^) and most importantly, most of the rooms are multilayered, making you visit the places from different perspectives and sometimes providing z axis fights.
In that regard, the Cobalt area SteadZ already mentioned is the prime example of the conceptual (I may dare say that) genius that lies in the map progression: You always have to keep your eye open for where to jump on next to find a way around the numerous barriers that are in your way. By the time of the latter third, I did find some of those "progression puzzles" a bit repetitive, though: Every time I saw crates or pipes I knew there had to be a shaft somewhere around. That is not to say you did not do your best to avoid staleness (for example, with moving objects); however, I had the impression those shafts were only built to get around obstacles, not always naturally integrated into the environment - in contrast to the great concepts of the buildings themselves.
I enjoyed the combats overall and (on Medium) I found the difficulty fair. There were some nice surprise encounters and the Titan was probably the most dangerous I had ever faced before. Also, the first WarLord was brutal, but managable. While the introduction of enemies was oftentimes energetic (either rushing at you or at least being alert), I do think there could be more variation in them approaching the player. For example, that one time a Skaarj took away the energy route in one of the last maps (not a fight, but could result in one). Or in the Ice Skaarj base, you could see a Skaarj through a window, pressing a button to open a door in order to reach you. Or (one of the most memorable scripted combat events) in Xidia, a ship packed with Skaarj crashes into a hallway - those moments are really cool.
The music in general was nicely picked and I liked the great variety in tracks. Though, sometimes, you could only hear the music through one channel, probably because you wanted to save some MB (kind of fake mono lol). I would advise you to use RMusicPlayer which allows you to play .mp3-files in Unreal. This way you can save MB and retain a good audio quality.
Regarding the story, I thought it was approriate. There was one WTF-moment with the reveal of the protagonists real name and some hints later on - I hope the last episode will offer a good closure to that! The ending of "Welcome to Site B" and the consequence of that caught me off guard as well, even though that very consequence didnt have a major impact on gameplay.
Thank you for this experience, you definitely succeeded with your aim to "give us a blast". My pure playing time of 10 hours in the score tells that this pack alone rivals ONP or even the mother game in length since every map (except The Dam) offers so much content or at least keeps you long enough on your toes! This really sets the bar high for the final episode.

Prisons of the Unforchers Retold - more info: https://www.unrealsp.org/viewtopic.php?f=4&t=4565