The author utilized Dehacked. The wad is tough, can get very slaughter-ish and hectic sometimes, but it's fair.
Also, the wad featured a pretty humorous story™. Check it out, but remember to play on HNTR/HMP if you aren't used to slaughterwads.
What's done is good. The gameplay can get pretty tough, but it never feels unfair. Overall the level & hub design is good. Pretty much the whole time I was wondering just where to go next, eventually finding it each time. There are also some neat, creative little puzzles (particularly the memory test with the Ice Golems) here & there. In this way it does a good job replicating the style of the original game. The biggest issue is that a lot of areas are way too cramped. Not only physically small, but crammed full of blocking decorations that impede your movement. The other issue is its unfinished nature. You'll end up at doors that say "access denied" and eventually have nothing left to do, and the lack of resolution is a bad feeling. But I would still recommend what's there for Hexen fans to check out.
"In this great solar eclipse all light shall starve and perish,
As phantoms of the astral abyss drain the cosmic life force... " - (Demoncy - Opening the Lunar Bloodgate)
Therefore, Moonblood has been finished, played through the Eternity Engine 4.00.00 Voluspa on UV difficulty. Interesting to see where the so-called overhaul of old levels led to, but we'll get to that in a moment.
So what's this about? Moonblood is a 32-level megawad consisting of gameplay focused maps with puzzles and nonlinear progression in mind, featuring new textures, music, menu background, status bar, intermission screens, and one boss enemy. It is divided in 6 episodes, and similar to Plutonia in terms of difficulty and enemy count, but much less generous with the ammunition, while being similar to the early levels of the original Scythe in terms of design and aesthetics. In fact, conservation turns out to pay off greatly in most maps, since, despite being pretty accessible, it's very easy to mismanage your resources and end up in awkward positions against few or mid-tier monsters. The enemies are generally placed in strategic positions, thus taking a moment to look around (or in the distance), or listen to the sounds in the environment can prevent some stupid deaths (or being sniped by a random hitscanner in the distance, be it through a window or out in the open). It takes place almost exclusively on techbases, with a more natural-looking or hellish map here and there.
As implied, the difficulty curve is traditional, starting easy and getting more difficult as you progress, with a (surprising) slight increase with each episode. Surprising because, on a surface level, all of them start rather easy, but don't let the guard down as there are a few surprises on the way, likely to keep the player focused and not fall into boredom. Indeed, if it looks easy, then it probably isn't, although after a while the traps do start becoming predictable (and irritating) as the formula doesn't change. After all is said and done, the journey ends with a battle against a re-imagined Mother Demon (Doom 64), firing Mancubus and Revenant fireballs, as well as rockets. A fitting conclusion, but the maps don't really anticipate the end since the difficulty doesn't get any noticeable ramp up, and neither does the enemy count nor the landscape changes dramatically.
What Moonblood appears to do very well is providing a nonlinear and generally puzzley element to its maps, and neither ever becomes an issue since the levels don't involve excessive backtracking or have cryptic progression, so you don't end up running from one side of the map to the other and still not find the way, or spam Spacebar on the walls or shoot them until some random door or switch triggers somewhere, a problem other wads/maps that offer both elements easily end up doing, becoming painfully confusing in the process, and losing all the fun they could offer otherwise. They're also not dragging on or have complexity for the sake of having it.
Perhaps the biggest problem of Moonblood lies in its roots. According to the description, it began as an overhaul of the author's older maps, and this is especially noticeable early in the game. The earlier levels have a dated look, not too dissimilar from those found in Doom 2, and yet, less impressive than them, giving the impression of belonging somewhere in the mid '90s, but aging relatively poorly. The gameplay is thankfully engaging and fun, so this does not become a very apparent problem that ruins the experience, and the more progress you make, the better the maps get. My favorite maps are those from Episode 5 and 6. In conclusion, Moonblood is a fun "little" megawad which manages to deliver a fun and interesting experience that doesn't last very long, but suffers from featuring revamped levels which don't end up standing out (or even look modern) despite the author's efforts. It could have been better if they were ditched in exchange for something entirely new. Do check out Exomoon after you're done with Moonblood as it lacks the shortcomings the original had, and brings both new and old things to the table (you'll have to discover them on your own, no spoilers).