Racking up high combo counts in Batman: Arkham Knight is super fun, but I suck. I get too involved in the mashing of buttons and [fart noise].
Sean Mitchell doesn't suck. Quite the opposite. Watch him rack up a 683 combo and marvel at how easy he makes it look.
It's not easy. It's hard. Really hard. I remember trying to get achievement on the 360 version of Arkham Asylum and really, really struggling to get combos upwards of 20!