Those of you who like the Ironman Speedruns the leaderboards for it are updated and pretty, have fun http://www.speedrun.com/ssbwiiu/full_game#1v1_Ironman
For the CPU ironman, how are stages chosen? Both of the current runs have done it different ways. The No DLC run does random omega stages, while the DLC run picks legal stages (Town and City, Smashville, etc.)
Both are allowed, it's a matter of preference. I'm not a big fan of some stages, and rather than just play on a few tournament legal stages, i found it more helpful to have a normalized stage setting. Since all Omega stages are tournament legal, I just decided to go with those. Any combination is permitted by the current rules, permitted that whatever stages that are enabled are all tournament legal.
