I just beat File 5 so I'm not too far in, but it's interesting to play these chapters anew without a worry for rank, Red Matter Collection percentage etc. Not being able to rely on Skills like Slow Shot, Round Swords etc. really helps you appreciate the combat more as well. In my main playthrough I barely attack myself, while here I'm doing a lot more work. Meter-management also is a lot more important, a single charged Bullet Time Arrow shot takes 99 meter and Blade Mode something similar, so you're always on the hunt for Red Matter mid combat.
What mostly took my attention though is how easy it is to absolutely melt things. You can buy Spicy Cobra (50%+ Attack) as early as File 2, same with grenades. And Fishy Water soon after (+100% Attack, +10% Crit, -30% Defense).
For the first big foe in File 2 I started with a grenade to knock him back. Then another while he was grounded, popped a Spicy Cobra, chained him up, attack him from behind with the Baton and Legion and as he escaped threw another grenade and chained him up again. Dead in seconds.
File 3 boss, Arrow Nemesis, died quickly to Fishy Water + Gladius in the air, killed it in 59 seconds.
For the File 4 boss, that giant plant, I started with Arrow Legion going wild on his face while I chugged grenades. As it fell to the ground I popped Fishy Water, threw the Gun Turret out (you get one from saving an ally earlier) and attacked with Arm Legion. Dead in less than a minute as well.
A lot of the fights really revolve around resource management now. I mostly use Blade Mode to avoid attacks currently.
Absolutely fantastic game. Doing the run on PT Standard right now, since I can't do it on PT Ultimate yet.