There are several 'hidden' techniques within the game that allow you to build up your super meter faster; you will see a notice on-screen when they are performed successfully.

CHAIN ATTACKS: The ones you'll use most often. All viable.

Chain Attack Lvl. 1: Step 1: Punch x2 or Kick x2, Step 2: Jump Step 3: Air Attack (Punch or Kick)

Chain Attack Lvl. 2: Step 1: Any Stun Move (Punch, Punch, Kick or Kick, Kick, Punch) Step 2: Punch x3 or Kick x3 OR Chain Attack Lvl 1

Chain Attack Lvl. 3: Step 1: Any Stun Move (Punch, Punch, Kick or Kick, Kick, Punch) Step 2: Any Juggle Move (Punch, Punch... Punch, Punch or Kick, Kick... Kick, Kick or Kick, Kick... Kick, Punch or Punch, Punch... Punch, Kick)

Chain Attack Lvl. 4: Step 1: Any Stun Move (Punch, Punch, Kick or Kick, Kick, Punch) Step 2: Any Charge move (Literally any move involving holding down the punch or kick button)

OTHER STUFF: Some are viable, some are not.

Bowling Bonus: Occurs when you kick 2 or more enemies during one Batgrapple swing. Given the lagginess/weak damage output of the move, it's better to save your points and omit Batgrapple altogether during a speedrun.

Counter Grab Bonus: If you are grabbed by any non-boss enemy, simply press the grab button quickly to free yourself and prevent them from damaging you. Generally speaking, you don't ever want to get grabbed in a speedrun, but this bonus is a lifesaver when you do, as most opponents' grab attacks are extremely lengthy in duration.

Dash Attack Bonus: Occurs when you immediately follow up a roll with an attack (the roll must hit an enemy). Very difficult to space as often you will roll past your intended target, but helpful when you get it.

Hit Streak Bonus: Will appear periodically during a hitstreak of 20 or higher. Bonus immediately goes away if your hitstreak is broken. Is THE fastest way to build up meter, but also the most difficult; stacks with other bonuses.

Taunt Bonus: Occurs when you hit any enemy that you have successfully taunted (They will have a '!' above their head. Make sure not to confuse your taunting with miniboss taunting; you won't get a bonus for the latter). Somewhat viable, it's occasionally useful to taunt and get enemies grouped together to try and hit all of them with a super move.

That being said, BE AWARE that your taunt has a range, and if enemies are outside of it, they will not react.