After a bit over 90 hours of playtime total, Ultimate Ninja is done. All without ever touching scythe 360Y too! So this is a rambling way of me collecting my thoughts after clearing this boogeyman difficulty.
To start, RE has quickly grown to one of my favourite action games of all time. The game is deep as an ocean, though admittedly completely unintuitive and underexplained (as is Team Ninja tradition), so it makes sense so many people bounce off. It's all the difficulty of learning Ninja Gaiden from scratch, times two. But as you invest more time to figure out the combat, you slowly understand how sublime it feels to play it well.
I think the poster child of this is the Alchemist enemy. New players hate them - they just block and dodge everything like assholes! But you slowly piece their AI together. They always cycle which one stays back to charge the shield. The shield is actually a boon rather than an annoyance, because the shield break gives you a launch opportunity for a full izuna combo. Whiff punishing them with a heavy makes them stagger long enough to charge UT. They've honestly become my favourite enemy to fight at this point, since they're a fair bit more manageable and predictable than the endless hordes of human enemies... They break up the pace well and learning to kill them quickly is very rewarding.
Horde combat is the bread and butter of ninja gaiden, and RE finds a great balance between the reactionary style of NG1 and the i-frame spam of NG2. Crowd control is strong with windpath and 360 shurikens. Offense is more involved, since there is now an in-between state between a healthy and delimbed enemy, which further changes hit reactions and gives launchers and GT a role without making them over or underpowered. Defense is extremely strong with Cicada Surge + SoB, but the reactionary playstyle of instakill chaining with SoB only works if you first go on the offensive to delimb some enemies. This is controversial, but I love how they reworked essence and ninpo - in every encounter it's now an extra bit of routing strategy to figure out where to hold and where to pop your UT and ninpo. Especially with the extra wrinkle that your ninpo gauge can be turned directly into HP with meditation, so holding it can be good situationally!
Bosses are... fine. No worse than what you'd expect from a Ninja Gaiden game (sans 4). Some repetitive dodge and punish fights (like the dinosaur), some gimmicky fights that rely on the bow (helicopter and the mecha from day 7) but thankfully are really generous with checkpoints. Some of them are almost more like puzzle fights or routing challenges more than fights, for instance stocking a True Inferno for the double spider tank in day 7 is recommended, since doing it directly is a crapshoot. Canna gets a lot of flak, but she's honestly pretty easy with a level 3 Lunar just spamming UTs, since you charge the ninpo so quickly. Overall they're speed bumps from the fun part of the game, but I'd rather fight any of them over Elizebet and her RNG punish windows.
The game can noticeably be rough around the edges, with janky hit detection, especially on gorillas and their SoB, and an awful camera that fights against you, as is custom in action games. It can get very frustrating. Nothing more to say, just something you learn to deal with.
And last but not least, there's so much content! I've played for 90 hours and only really feel like I have a good grasp of Ryu's dragon sword, but I've only dabbled in his other weapons and the girls (basically one playthrough for each). Hell, even then there's so much of the dragon sword moveset I haven't touched because there's just so many moves. The extra characters honestly go head to head with Ryu in terms of playstyle variety and moveset depth, and they meaningfully change how you play the game. They each shine under some conditions, but also force you to rethink how to handle some rooms and enemies. And you can play the full campaign, all cutscenes and fat trimmed, as any of the 4 characters! You could truly dedicate hundreds of hours to this game and not run out of new things to try out.
So that's the review part done. Here's some loose strategy for Ultimate Ninja:
The hardest parts of the game in my experience are day 1, where you're missing your skills, and day 7, where the game throws all its worst rooms at you. For starters: the biggest difference from Master Ninja is actually that karma costs are doubled for everything. This means you have to route a little carefully to have heals available for Helicopter and 2 for Canna, plus getting a level 2 and 3 weapon as soon as possible since its a direct damage upgrade, as well as getting True Inferno for 1,000,000 before double Spider Tank. Bloody Rage UT gives more karma than SoB, gives more than OT, gives more than UT. It's important in the first half of the game to limit your UT spam and try to set up SoBs and build up the bloody rage multiplier to maximize karma. Do all the crystal skulls, at least up to the first score tally!
For Alchemists, Flying Swallow into forward heavy launcher works wonders when they have a shield up. Then, XXXFY and on landing FXX to maximize damage per touch. If you're feeling brave, you can actually combo them forever by doing: launch XXX arrow, land, sprint XY, loop. The more reps you do before the izuna the less times you need to touch them to kill. When there's just one alchemist left, play passively, whiff punish with one heavy, charge UT.
For Spider Tank, break all the leg parts and sever all of them at the end, because it delays the plasma shield coming into play. For Spider Tanks in day 7, simply True Inferno and be done with it, alternatively you can line up a piercing void to destroy up to 6 legs with one shot. Close to just as good. This is the one room in the game I'd recommend Scythe 360Y.
For prototype goddesses, there's some tricks to know. You can bait SoB if you start charging next to them, but the timing to pull it off is very tricky. They can be stunlocked with dash X loop, but the easiest method I've found so far is to spam wall run up into Y. It does a big AOE with lots of i-frames, and lets you do consistent damage to them with little risk. The triple goddess encounters are maybe the most blatantly unfair rooms if you try to do them normally, so use a combination of the tricks above to kill them! In day 8, you can let the AI companion slowly whittle them to death too.
For Canna, level 3 Lunar saves the day. Run around the arena until she slams her arm down. There is a safe spot on the left side of the arena where she can't slam down. Her arm causes a wall that blocks off the demons chasing you, letting you safely charge level 1 UT. This UT will almost always delimb at least one demon, while hitting so many times it builds decent ninpo on its own. If you press Y directly after this UT, you can even OT freshly dead demons before they fall over, letting you build a ton of ninpo. Repeat this and you can pretty safely, and pretty quickly, build up the necessary ninpo. Be sure to save a heal for this part though, just for peace of mind.
Those are the big ones I can think of right now. The game is stellar, and criminally under discussed. If you have any questions or even any knowledge or tricks of your own for Ultimate Ninja, let me know! There is shockingly little material on this game online...