well i did it. Not the best one, but very first to go!
Thanks for showing interest!
Me plan is to do that in 7-8 hours, i believe it's possible in 6, but anything below that point i suppose could be done by only aliens :D
Zeromus is must have, yea. It saves a lot of time on last stages, and not only at stage 100. As well he does his best during Chaos, Abysteels, Ultima, Deathgaze, Gilgamesh, Magic Pot, Shadowseer and his fellows, 3x Supreme tyrants, Elza/Rikken/Pirates.
Warp motes are great, but Big Bang is much more faster and better during stage 86.
RNG moments are present too, unfortunatly. Like stealing Zodiac Spear from Biding Mantis, stealing Brave Suit, Wyrmhero blade, Excalibur (less rng based one). That's what will mostly affect on time.
However, i keep my hope for someone who'll find better strategies.
It might be possible to start trials right after you beat Belias, but not Vossler. As you know if you don't go further after defeating that Esper you can save Vossler and have second job. Guests Wither/Expose could be extremely useful during trials.
I would like to see such category here.
Rules: New Game, not minus, not plus
Goal: complete trial mode