Sustained streams, my hits go off-sync past 6 notes. Groups of 4 eighth-notes, I'm too used to groups of 3 eighth-notes that the additional one at the end messes me up completely. Complex patterns of stacked notes Circles that are right after a spinner
my main weakness is background pictures and videos and that prrson jumping from the edge of the screen when you reach certain combo, thus I switched them all. Otherwise my eyes can't concentrate properly