Finally managed to get this! Video of strategy included at the bottom of the solution.
Tips:
- The falling block room is pretty RNG heavy, but keep practicing and any run with 35hp+ should be solid enough to pull off the S rank if the rest is executed well.
- Level 3 spur (not maxed) and level 1 nemesis can shoot through unactivated deletes if you are pressed up right against them. You can get away with not using this strategy at the end before Heavy press, but I'd recommend trying to learn it.
- Always be boosting and close to the ground! Especially during the falling block room as you then have more reaction time too
- I use level 2 blade for heavy press but level 1 spur spamming might be faster or nemesis if you can dodge the exp well.
- For Ballos 1st form, use blade two and shoot straight up and dodge him; the size of the blade can still hit him and it makes for a quick nodamage 1st form
- You'll need 23 hp for Ballos' final form to do the fast kill strats. If you don't, level 3 blade on the spinning platforms will take him out fairly quickly too. For the fast kill, switch to blade 2 and face away when in his eye so you can unload curly's level 1 nemesis into him at blade 2 speed.
Good luck!