Thoughts of Chaos is the epic conclusion to The Antioch Chronicles, a large-scale custom campaign. TiC weaves together a narrative made by many different characters from different faction and have them slowly converge until the finale. It features acceptable voice acting (the protoss voices will grow on you, and it gets better in later missions), and quality editor work (terraining, models, etc), as well as a well done and entertaining story (despite the ending being too cliche) by my admittedly low standards.
However, any fun that one would normally get from the story is instead leeched away by 110% mediocre gameplay, which mostly seems like a way to pass the time between story segments rather than engaging and enjoyable.
The gameplay, first and foremost, suffers from slow pacing. There's plenty of long winded backtracking through empty and very weakly defended areas in both macro and micro missions. Here's an example: TiC has a stealth mission, reminiscent of HotS' ship infiltration mission. However, instead of combat, you're greeted with (admittedly well-thought out) puzzles, halfhearted enemy detection patrols (you don't interact with the guards other than just walking out of their zones), and halfhearted kill defenseless, undefended structure to progress. It got to a point where I tried to break the monotony by attacking some random guards and escaping the detectors gaze. This gets back to what I previously said about "waiting x minutes", you're moving through the ship for a certain duration to get to the next puzzle, enjoyable gameplay be damned.
Difficulty, like many aspects of gameplay, didn't seem to get much thought either. "Hard" in TiC means "WoL casual". Many hero units are broken, and with minimal micro they can multiply a small force's effectiveness by tenfold. Many missions can be beat by getting 10-20 units and just steadily rolling across the map. But in two missions it's very, very, hard, unless you understand the correct choices you need to beat the mission (which would require editor diving or some really lucky guesses). Of course, such information is only going to come to you once you lose the mission once. As an example, there's a holdout that features extremely high tech ground units (archons, reavers, ultralisks) with a few air superiority fighters and dropships. Suddenly, on the last few waves, the mission throws the curveball of 2 carriers (capital ships) per wave. Hopefully you built enough anti-air that you couldn't know that you'd ever use. If there had been any hint in an earlier wave, I would have enjoyed the mission. It was on my skill level, a nice terran holdout with some interesting twists. Due to not seeing any indication, I fortified my tank line and suffered, and lost a lot of .
Bosses have HUMONGOUS HP bars, backed up by tiny amounts of damage so that phase transitions, many of which are accompanied a cutscenes or "action pauses", are played a significant duration apart (have to have SOME space between emotional moments). Combine this with high cooldown abilities, and I had trouble staying alert during boss battles, as rarely they did anything cool, interesting, or required effort to dodge.
In closing (TL;DR): DO NOT PLAY Thoughts in Chaos if you're looking for a campaign that gives you something to do. If you must see the story because you've seen the first two (and you should see TiC in that case), use cheats (i.e."move" or "god") or watch Jayborino's videos to avoid interacting with the gameplay as much as possible.