Just attempted and cleared 1-vs-100 for the first time (as Min Min). It's more interesting than I expected: I assumed everyone would just get a standard 100-man-melee on a neutral stage like in SSB, but instead every character is paired with their home stage, where the enemies mostly sport arms from that character's default loadout, as far as I can tell, but widen their arm selection as you get further into the challenge. Each stage has a separately tracked record time; clear the home stage and the 1-vs-100 challenge there becomes available to all other characters. A healing circle drops after every 10 kills unless you are at full health, in which case you get one of the fire bombs to launch at the enemies and cut down on your time.
Also good practice for trying to hit a Helix.
The target switching is clumsy, though not quite as bad as it is in 2v2 because at least the targets are clearly marked and not always bunched together. To be honest, anything involving multiple targets in this game seems to be an afterthought in an experience self-evidently designed to revolve around the 1v1. Here I lost some time just in the course of acquiring the nearest target (usually one deep in the noodle bowl, at that) so I wouldn't leave my flank exposed.
Still figuring out how to make good use of it myself, but the extra deflection gives you some breathing room to safely have both of your arms out or take to the air. I don't know how useful that is in high-level play (where the dominant thinking right now, from what I've read in this thread, seems to encourage staying on the ground so you don't get punished on landing), but against the CPU I find that room for error useful; it lets me play a little more aggressively.
