The 'Time Attack' challenges range from obscenely difficult to completely impossible. Seriously, there's one with only companions, so you can't control it at all. I still lose that one even with companions upgraded to the max and buying all available runes.
My recommended to-do list for this game would be:
Increase time on time attack missions
make companion AI not suck (It's fine for the assassin, since he's got so much speed, he can avoid being damaged all the time, but the other two shouldn't be running halfway across the map every other kill.)
Increase reward on the challenge stages. There's really no point other than pride right now. If the stage is more difficult, there should be a greater reward than the normal stage.
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