I think there's a glitch of some sort in the brawl mini game specifically for the options that have a 3 key combo. I can beat the 4 and 5 key combos consistently on normal (but not hard) and I never fail them on easy. But even on easy I fail the 3 key combos pretty frequently no matter how fast I do them while having way more time than I need for the 4 and 5 key combos on the same difficulty level against the same opponent. Not a huge deal since you can just repeat the fight until you do win but it's still annoying.