My playthrough notes

I should have learned Flame Toss before starting the Cathedral. The Naga-ettes have huge HP pools and the Henches have very high defense. Everything felt much better once we had Flame Toss.

Yakra

This fight was frustrating. Frog healing with Slurp and Crono+Lucca dealing damage with Fire Whirl is the obvious strategy here, but Yakra's counterattacks are frustrating. I think Yakra treats Fire Whirl as Lucca's attack so even with him close to Crono you're triggering them. Yakra works fine if you just use basic attacks but I think a lot of players will get discouraged here.

Dragon Tank

Oh boy, Dragon Tank. This fight was intense and unforgiving. Starting off with Yakra and Dragon Tank certainly tells the player to expect to have a hard time. (I know it's outside of the scope of this mod, but I've always thought Crono's Slash should dissipate the Wheel's attack like it does against Masamune.) Definitely a good start to the mod.

The next thing I was looking for from the mod was a reason to use Hypno Wave or Provoke. I never found a use for them in the base game. I was pleased to see that they worked against the plants in the Future to stop them from healing--but they also fall to a single Fire Whirl. Oh well. Those two Techs are so disappointing.

I didn't notice any difference to Guardian, but I was grateful for a breather after Dragon Tank.

R Series

This one took a few tries. The difficulty increase meant I learned something new about the R Series: I got to see the Area Bomb counter used when there's only one robot left! That was a nasty surprise.

Heckran Cave felt unchanged.

Zombor

This one felt unfair. The fire breath could one-shot Crono or Marle. He could also follow up his party-wide laser beam immediately with fire breath, which was overwhelming. Constant Revive use along with hoping he used his drain attack (which did an inexplicably small amount of damage) was the strategy here. His HP is low enough that I didn't have to get lucky for very long to finish him. Not very fun.

The Free Lancers were challenging enemies in the Denadoro Mountains. I thought it might be a perfect time for Hypno Wave or Provoke to shine...but they just provoked counters and got us killed. Unfortunate. The gauntlet of four encounters resulted in a game over. I'm glad to have random encounters keeping me awake.

Masamune was straightforward. He seemed to get stronger as the fight went on, which made for a tense finish. Nice one.

I didn't spend any time on the Hunting Range in 65,000,000 B.C. which meant Ayla was the only one with a Ruby Vest for the Reptite Lair. That meant the Eaglets and Megasaurs could one-shot us with their fire breath which kept things interesting. Kiss at 3 MP was a pretty big disincentive to use her for healing, which I guess is fine.

Nizbel

I was worried about this fight since his damage output is pretty high even in the base game. Electrical discharge followed by a stomp was in fact give a game over. Marle got one-shot by the electrical discharge, so I switched her for Robo who...also got one-shot. I think this was my introduction to Robo's low magic defense. He didn't stomp immediately after a discharge on my second attempt, so Crono and Ayla were able to stabilize and finish him off. It took three or four cycles of discharges to take him down, so I felt I got lucky there.

Slash and Flea

The swordsman bested me once. I switched Lucca out for Robo for more healing and to finish him quickly when he started countering.

Flea also got me once, probably due to overconfidence. Subbed Marle in for Aura Whirl. I think he was setting more statuses which was interesting. Blindness doesn't seem to affect Techs at all though.

Magus

Chef's kiss. Perfectly tuned. I don't want to say too much about it because I think people should experience it for themselves. I fought at levels 22-24 and Frog survived Magus' Lightning with single-digit HP a few times, but never died to it. I find myself wanting to rave about how great the fight was, but again, I don't want to spoil it at all.  It took me half a dozen attempts to bring him down. It's worth playing this mod for the Magus encounter alone.

Nizbel II

The team's greater selection of Techs for the Nizbel reprise made him not as threatening as his first encounter.

BlackTyrano and Azala

I had a false start with Ayla still wearing the Berserker. Oops. Falcon Hit behaved strangely here. Crono and Ayla acted confused and she refused to toss Crono. I still got the damage on Azala but it missed Tyrano. I don't think this is how it worked in the vanilla game(?) but it's been a long time for me. Other than that the fight didn't feel any different. No complaints; it was fine to have a couple of breather bosses after Magus.

Not much to say about the first trip to Zeal. The sewers were actually quite challenging once we were on our way to pick up the Epoch. The fact that the monsters were tuned for this point of the game but their Exp rewards were not was annoying (as well as the chest still containing a Bolt Sword!)

Mud Imp and Red/Blue Beasts

First of all, I should mention the 2 Beast encounters leading up to this boss. Holy crap were these a shock. 

On the Red/Blue Beasts, I was looking forward to actually getting some use from Hypno Wave--I'd watched a vanilla speedrun and seen it used to good effect here. I tried it five times in a row and it never worked. Was it actually disabled here or did I get unlucky? Either way it made me sad. I can't imagine going out of your way to make Hypno Wave even worse.

Anyway doing the fight the intended way worked fine.

Mt. Woe monsters were tough as well, but felt like a reprieve after the Beasts. I learned Boogie here, which for some reason costs Ayla 15 MP? And of course the time I tried it out to verify it wasn't a display bug, it had no effect either. It's even worse than Hypno Wave! Also Falcon Hit misfired against the Bantam Imps for some reason.

Giga Gaia

It felt like the Red Mail and Black Mail were required to survive here, but maybe not. I knew what to expect going in and got him the first try. Falcon Hit was strange again here. Its damage varied widely from 60 to 2000 on either hand. What is going on with Falcon Hit?

Ocean Palace

Can it be???? Hypno wave WORKED?!

Golem Twins

I remember these girls being a real problem in the vanilla game, but I recently learned they don't take any turns if you keep hitting them with different elements, so that's what we did.

Blackbird Dalton

Unremarkable...unless you hit him with Magic? He Fire 2'd and hit the party for 1000 in response to a Cube Toss. Not cool.

We picked up Magus and immediately went to Ozzie's Fort to get his gear. Death Peak was unremarkable. I did the sidequests in this order: Son of Sun, Masamune, Rainbow Shell, Ozzie's Fort, Mother Brain, Sunken Desert.

Son of Sun

Still trivial with both Red Mail and Red Vest. The vulnerable flame was on the bottom right through 4 or 5 shuffles. Possibly bugged?

The Northern Ruins were extremely tedious to clear out. What's going on with their HP totals? The Sentries do 1/2 HP with their normal attack but their drain does hardly anything. Very tedious fights since most everything here dodges physical attacks. Our Magic Defense was still far from maxed at this point so I think something is off here. This was the start of a pattern of endgame content feeling like it was wasting my time.

Rust Tyrano

Another trivial fight. It's impossible to lose with the Red Mail and Red Vest equipped. I was worried for a moment when his countdown sped up that he would chomp and drain life faster than we could do damage, but instead he stopped chomping entirely and did fire breath more often, which is the opposite of a difficulty increase.

Yakra wasn't trivial at least, but still not difficult.

Great Ozzie, Super Slash, and Flea Plus

Extremely long fight. Their damage was trivial at this point (96 M.Def on Magus, 85 on Ayla, ** on Frog, Barrier on everyone). They would certainly be challenging without high M.Def given their constant counter attacking. Their triple tech (Delta Force) did ~300 to Ayla and ~50 to Magus. The fight did teach me that status effects override Barrier on us, so that was nice at least. Still, not worth 25 minutes out of my life to learn that lesson. There's no reason for them to have so much HP; either you can survive their attacks or you can't.

Mother Brain

I think this might be the first fight I encountered that was redesigned. I like the new twist on the fight, although I was very frustrated while learning it. There is no reason to have such high HP on the Displays. The only lesson the player learns before all the Displays are down is that damaging Mother Brain is pointless because they heal for so much. That lesson is learned quickly--but it takes a long time to kill the Displays. It is tedious.

Once the Displays are down, Mother Brain's attack pattern changes which is the second lesson that the player learns. Black Mail trivializes the first part of the fight (another reason it is so tedious) but that stops working here. Gear must be selected carefully to survive her attacks and also prevent her status effects.

The last lesson the player learns is that she must be killed quickly. These changes all add up to make for a challenging (and thus satisfying) fight, but having to go through the tedium of killing the Displays on each attempt in order to learn the second and third lessons makes for a frustrating experience. Their HP could be greatly reduced without affecting the difficulty of the fight.

(I will note that Robo hadn't learned Shock yet at this point, which would have helped with our damage output. Magus and Ayla have been mainstays of my party since Death Peak, so Lucca, Robo, and Frog had been missing out on Tech points. Crono and Marle maxed out some time ago.)

Retinite

Not much of note here once your Magic Defense is maxed. 

I still had some Techs to learn with some characters, so I was using a B-Team as I started the Black Omen. Poor Lucca was at level 51, Crono, Marle, and Robo at 53-54, and Ayla, Frog, and Magus at 57-58. Crono, Marle, and Robo were my A-Team.

Mega Mutant

Two of my characters didn't have status protection, so Mr. Mutant made short work of us. More attention paid to our gearing led to a successful kill. This was a theme for the Black Omen--having the right gear setup (balancing Protect, Barrier, and status protection) was key to many encounters here.

Even most non-boss encounters felt like they needed the right gear. I used save states over and over throughout the Black Omen. It would have been very tiresome to clear the same fights over and over after reloading from a save point.

Tubster

An honorable mention here for the Tubster. He may have taken the most resets out of any encounter in the Black Omen before I figured out what was going on. A nice little interlude from the boss fights.

Giga Mutant

A very intense fight. I had spoiled myself on the fight when reading about the mod so I took it down without too much frustration. I didn't like that it seemed to require a specific party composition--that violates the core design principle of Chrono Trigger in my opinion. The fight certainly pushed the limits of what's possible in Chrono Trigger's battle system. Well done on the design and balancing of the fight (though I think his damage should be pulled back 5-10% to allow a little more flexibility in party composition).

Terra Mutant

This fight dragged on for quite some time as he helps you kill his base and then his damage output is fairly high once he's left alone. I think, like many bosses and encounters in Lavos Awakening, his HP could be slashed significantly without affecting the difficulty of the fight. As I said before, if you can survive his attacks for 5 rounds then you can also survive them for 50.

Lavos Spawn

This one took a few resets as well. Damage was fairly high, and he often gets off a double needle attack with no chance for me to respond in between. What's more, your damage options are fairly limited against the Spawn. A conservative approach (keeping my HP very high) was important here, which made things take longer than they had to. With the length and number of all the encounters in the Black Omen I was certainly feeling fatigued at this point.

Zeal 1

This fight was mostly notable in that it seemed to require an AoE full heal, which was annoying in that it limited your party options for the next two fights. I would have liked to bring Magus to see his interlude with his mother during the Zeal 2 fight, but felt rather constrained. Maybe I'm wrong and it's possible to do enough damage to finish her off before her damage ramps up.

Mammon Machine

This fight could certainly be challening if you were to do it the intended way. You'd have to be smart about your Tech use and, together with the healing requirements from Zeal 1, it could really test your knowledge of all the double and triple Tech options before you. But using counterattack relics totally no-sells Mammon's mechanics, so ¯\_(ツ)_/¯

Zeal 2

Not much going on here. If you beat Zeal 1 and Mammon then I can't imagine failing here.

Lavos Shell

Not much to say here. Boss rushes can be fun encounters, but here it's jammed in the middle of 5 other boss encounters so it's not really a satisfying place for it. Maybe if his damage in his various forms was tuned to be a threat it would be more interesting?

Inner Lavos

A satisfying encounter. This once has it all: high physical damage, high magical damage, status effects, and some arms to kill before you can destroy the body. What more can Chrono Trigger offer?

Lavos Core

The interesting part of this fight is that it subverts your expectations, and the 'bit' is the true core here. Of course a hardtype mod has nothing to say about that, and so the fight was over in short order.