Injustice 2

This achievement unlocks once you've used all 28 non-DLC characters' Supermoves. This is done by filling up your meter on the bottom of the screen through dishing out and taking damage, then pressing + when the meter is filled and "Supermove available" appears above the bar. You'll also need to have beat Story Mode so you can play as Brainiac.

There are 9 other achievements in the game tied to using Supermoves with specific character matchups so you will automatically earn progress towards Feeling Super doing those. The characters linked to the other Supermove achievements are Swamp Thing, Cyborg, Green Arrow, Doctor Fate, The Flash, Green Lantern, Aquaman, Superman and Joker. If you're having trouble remembering which characters' Supermoves you've used but you happen to have all the matchups achievements, strike all 9 of these characters off your list and try someone else!

These do not track in Practice and DLC characters are not required.

Legendary edition of this game has 38 Characters in total, but in order to unlock this achievement you only need to perform Supermove (+ while all your 4 meter bars are full) with 28 characters included in base game.
The achievement will keep track of Super performed online or offline, in both single or multiplayer (but not in practice mode).
If you let AI play for you, and your character perform a Supermove, or if you kill your rival with the first hit of Super (thus skipping Super animation), it will also count.


Keep in mind that there are other 9 achievements related to defeat a specific rival by performing a Supermove with a specific character, so if you already have those achievements you'll only have to check out 19 remaining characters.

Here's the list of 28 characters needed for the achievement (=character with his own supermove related achievement)