By the time you get to the third UAA showdown in No More Heroes, you’re in the thick of it. There’s no reason to treat the player with kid gloves anymore and that’s exactly what happens in the Shinobu fight. Shinobu ends up being an important character in No More Heroes as a series, but for now she’s Travis Touchdown’s first real challenge. If you’re playing on Bitter you have a real slobberknocker on your hands, but you’ll be able to scrape through just fine otherwise. Assuming you have the combat down by this point, of course.
The first thing you’ll notice when the battle starts is the more complex arena here. The first two fights take place in wide open spaces, but you’re in a school building for the Shinobu Shodown. This doesn’t mean a whole lot, but it does mean there are things like pillars, hallways, and other geometry you have to be aware of. There will be blind spots and it can also be more difficult to get your bearings in relation to where the fight’s hail mary battery and health pickups sit.
Most of the time it won’t matter a ton though, because this fight is face to face. Shinobu is fast and powerful, and more importantly impossible to disrupt. You’re going to have to wait for openings, and give up on trying anything tricky. Shinobu can and will mess you up with multi-hit combos, and several big, unblockable moves. It is technically possible to get a stun and a suplex, but the window of time is so precise that’s not worth trying for unless you’re a master.
Once you whittle Shinobu’s health down enough, she’ll go into a second phase and get a couple of new attacks. These are telegraphed by charging much like her other big moves, but with devastating properties. If the air around Shinobu turns white and she says “die” you’ll need to get out of the way as her long-range attack is upgraded to multiple shots. And if she sheathes her sword there is no margin of error; if you don’t dodge it you’re going to eat an instant kill move and have to start over.
That last phase will go on for a while, and you’ll have to just keep being patient and aware of your surroundings. If you ever lose sight of Shinobu you’ll need to turn and hammer that lock-on button to make sure you know what she’s doing. Try to keep the fight away from the pillars if you can, and if you need to run for the heal chests make sure you know what direction to run in so you aren’t wasting time.
Overall you just need to maintain your patience, and be okay with only landing a couple hits at a time. Stay on your toes, stay locked on, and stay sharp and focused on the differences in Shinobu’s charged attack animations.