Helpful Hint: Lowering video quality to the minimum setting on the Time Attack missions should decrease lag & make them MUCH easier to complete.
--
Also, I agree with purplecat's comment about the strategy being to mostly run in circles around the enemy and attacking occasionally, except I also make use of the special attacks (spirit wave & hurricane blade). To that end, I think the game play would feel faster/less monotonous if the player character's special move cooldowns didn't take so long. Perhaps cutting them to 1/2 or 1/3 of the current durations would make it more reasonable, especially with the tendency of the NPC allies to die pretty easily, leaving the player to face the horde of enemies alone.
 "Mighty Knight"){kind=icon}