Idk if Steam allows one to specifically review UGC, but frankly even if it does, I feel this one belongs here for anyone who might undertake to play 'The Deep One'.

First thing to know is that it was never completed. The story takes you to the beginning of Chapter 5 and then ends, best I (and anyone else who's commented) can tell. (Caveat: As of the date of this writing; the author has returned before after some years and picked up the story; they might do so again.) Still, to reach that point in Ch5 (Dunwich) requires a similar amount of playtime as the entire original game, so there's no need to avoid TDO on that basis.

Second, this UGC isn't easy. Some of the fights feel downright impossible the first time you attempt them. You may have to develop new tactics and approaches. This despite the fact that you import your character from the end of the base game, so you are quite powerful yourself from the beginning.

Third, the runners you can hire don't seem to develop throughout the UGC. This means that someone who's quite effective early on becomes a bit weak later. The runners you gain access to throughout the story offset that somewhat by being more powerful than the initial ones.. at least somewhat. (Gevrik, you might consider upping the Karma of the NPC runners from chapter to chapter.)

Fourth, if you aren't a decker, some of this UGC can be VERY challenging. The main NPC decker starts out weak, has no heals or shield, and is not consistently replaceable with anyone better unless it's yourself. Also, unlike the original game, you can access pillars in the Matrix without having killed all the IC, so sometimes zerging through Matrix runs is by far the fastest and most efficient way to complete those portions. (Something I hadn't realized: You can carry two instances of Suppression, either of different levels or one purchased and the other from the nanobots; that allows you to bring the alarm level down quickly and efficiently if you attain a state with no currently-active IC.)

Fifth, there are some bugs. I don't want to delve deeply into any of them here, but there's an issue with Essence that can dog your heels from the character import onward if you import a character with cyberware, the nanobots aren't consistently usable and they overwrite your 'Mark Target' ability if you have it, some quest progressions require workarounds like leaving and re-entering the zone, and the story can get confused if you do things in other than the order the creator envisioned (mostly leading to outdated dialog), and AP is oddly variable sometimes. Also toward the end I noted runners whose HP were less than their Body stat plus cyberware should generate. And don't listen to Zoex: she'll (thus far) never offer you those weapon and armor mods.

All the above having been said, the STORY is excellent and engaging. The mysteries you unravel are fascinating. Some of the quests have designs that are unique and engaging and that will challenge your flexibility in approach; it's not just run from place to place, pick up clues, shoot people, repeat (though, of course, there IS a lot of that). Even with its bugs and unfinished nature and quite difficult combat, this UGC is absolutely worth your time. I salute Gevrik on a creative artwork.