I posted my comment directly on the game at first, but I decided to repost it here so I can mention some spoilers.
I won on my first try. My favourite part was figuring out which enemies to fight and which I should just run from. I couldn't tell if it was impossible to run from some enemies, if the chance was just lower, or if I just got unlucky, and because you die so quickly and have limited resources, I had to take my best guess a lot of the time. At first I was fighting the Knife Aficionados, but I realized they take forever to kill and are easy to run from. I never fought a single Knife Knite because they looked scary and I got the run on my first try every time they appeared.
The MP disparity between Backstep and Deathblow created a fun rise and fall of tension. After you use Backstep once, you basically get 17 more "free" uses before you lose access to another Deathblow, so at first it feels like you can use Backstep carelessly, but then you start to hope you'll be able to conserve it. Then if you're forced to use Backstep the 19th time, the cycle resets. I ended up having 3 Deathblows to use against the boss. I wonder if I got lucky with the amount of times the boss ended up using Corner. Realizing that Corner reduced my healing power was another tense moment and made for an exciting climax. At that point, I just went for an all-out attack, and fortunately the boss kept using Corner a lot instead of hitting me.