alright i spent way too long on this. i tried to find something without a desperation potion, but everything was 20-30 seconds slower. it should be faster overall to get a desperation potion, so i looked at the desperation potion strat for eito. there are two possibilities for the eito battle on turn 2, and in one of them eito get armor. this results in not dealing enough damage to kill him. i tried so many things in turn 2 to get around this, and i couldn't find anything that wasn't significantly slower. i ended up using a metal fence on turn 1, and it miraculously solved the issue. i haven't confirmed that it's 100% consistent though.

here's my attempt at wave 2 without a spring trap. it requires 100 voltage, 1 attack potion, 2 agility potions, and 1 defense potion (i used 2 defense potions because i didn't have 100 voltage)

here's day 87. i didn't kill every enemy in wave 2, and i instead let them self destruct. i also used takemaru's "eat this", which would have to be unlocked alongside jury, impact stab, and sacrificial viper.

i skipped ahead to day 86. this one isn't too interesting, but it is worth noting that a desperation potion could be faster (but not enough to be worth getting the potion on its own)

for the desperation potion, getting the grades and the potion itself would waste at least a minute. getting the required materials doesn't actually seem too bad, and i think you should be able to get enough most of the time. it's not out of the question that it could be faster for any%, but it would have to save like 2 minutes in battles to be worth it.

edit: posted this before i saw yours lol

i came up with a backup wave 1, which you can use if you get armor. i also came up with a different strat in wave 2, where i lured as many enemies to the bus as possible, then killed them with righteous punishment and last resort crimson assault. i'm not sure i found the best way to kill the upper enemies though.

i got a turn 1 wave 3 without jury for day 55, but it is requires a significantly slower wave 1, so i think it is worth it to get jury. getting impact stab and potentially a few other upgrades while you're there is probably also good. day 65 is very random in wave 1, and immediately ending the turn does not guarantee that nozomi will die. you can dash her in a general area in front of the fake moko first, and in my testing she died every time.

i also went back to day 44 and found a turn 1 wave 3 that should be faster:

wave 2 needs to be slightly different, but i don't think it's much slower.

damn your day 29 strat is way better than mine. i modified your wave 2, and it should be a little faster

also, here's a strat for the day 44 battle. i tried many variations, and it's possible if not likely that there's a better way to do waves 1 and 2, but i just said fuck it and went with something that worked. you can do wave 4 without continually hitting the orange guy and save a few seconds, but i don't feel like recording this again

here are some strats for the battles on day 28 and 29. both are affected by randomness, especially the day 29 battle. both of these strats have no upgrades, and assume takumi deals the finishing blow at every opportunity.

day 28:

day 29:

The category is called "all levels" it really should include all levels.