I have to say I like the challenges, except for the challenges that don't allow movement. With -100 resistance, all of my characters die in 1 hit, so defending/countering doesn't do me any good. (Counter and they die, defend and they don't do damage). When I finally do defeat a significant number of enemies, there is always one that just skids back and forth and never actually attacks, causing severe weapon degrading annoyance. Overall though, it is a really good game.
Actually found a small glitch (I think) If you are using the ghost sniper's secondary fire, and are re-forming, it is possible for you to get hit before you are able to fire, causing you to drop down a level and not be able to fire at all, because the reformation never actually finished.
not sure, but does repeating the areas final mission count as training? if not, then you can use the bosses to train yourself up to the level you want.
 "Dash'n Knights"){kind=icon}
 "Bubble Tanks 2"){kind=icon}
 "Sonny 2"){kind=icon}