>>1875655
20 turns to fight through 10 rounds of enemies shooting at you. Bosses at wave 4, 7, and 10.
Your score is determined by the difficulty you select, with bonus multipliers depending on how many leftover turns and hp you have. Bring 2~4 healing memories. If you do not make it through the entirety of the 10 waves, you won't receive a score and won't use up an attempt.
Don't worry about correct guns or break; all enemies have 99 shield, and don't do much shield damage in return.
Contrary to the usual strategies, def debuff is not super strong here since enemy debuffs don't carry over. Focus on attack buffs, defense buffs, and maintaining crit rate throughout 10 turns.
If you did not roll for Eines and Amadea, you can still get a decent def buff if you have commander Kana and do the training quest.
Be sure to have a dolphin to cleanse stat downs like cow Yume or swimsuit Tsugumi.
After you beat Ultimate level 15, you unlock Impossible levels 16-25. Boss waves get an absurd jump in damage starting from 16 and I don't think it's feasible if you didn't whale the meta.

Also, don't forget to do the new daily tournament difficulty. There's new mats and there should be a new shop tab for it when the month rolls over.