In the discussion they mention:

> The major limitation of our project was the opposing player. Of course, we would have preferred training against human players who play Melee professionally.

An alternative training method could be through the use of the 20XX hack pack [0], a mod of Super Smash Bros Melee that adds, among many useful features, an improved AI. Here's a video of the AI from release 4.05 in action: https://www.youtube.com/watch?v=rzl5NXV5bHQ

The built-in SSBM AI is very noticeably different from competitive play, and the 20XX AI makes significant steps toward more human-like competitive play. It would be interesting to see the results if trained on these AI.

[0] https://smashboards.com/threads/the-20xx-melee-training-hack...