Intro:

Barry Allen, who's father was wrongfully imprisoned for the alleged murder of his mother (which Reverse Flash was responsible for, for those of you who don't know Flash lore) and was sentenced to life in prison. Barry grew up as an orphan, obsessed over ensuring his father gets the rightful justice he deserves and hence, he decided to explore criminology as a career path.

Aside from his personal life, Barry is the world's fastest man, granted speed powers and a connection to the "speed force" by a radioactive bolt of lightning, Barry took on crime fighting, and the alias of The Flash, donning a metallic red suit made with materials used on space shuttles. When approached by Bruce Wayne in an attempt to enlist him to the Justice League, Barry joined without hesitation, due to the lack of socialization in his life as well as the relative unimportance (in scale) of the work he did as The Flash. Barry went on to become arguably the most important member of the Justice League (in Snyder continuity) in taking down Steppenwolf. His most notable contribution being his reversal of time, when Steppenwolf's plan succeeds, and Earth is terraformed, giving the Justice League a much needed second chance at victory.

Notes:

Just gonna point out that feats that are also in the Theatrical Cut of Justice League won't be in the Snyder Cut section, as there's no point in this.

Feats:

• "Silica-based Quartz Sand Fabric, abrasion resistant, heat resistant" (same material that is used on space shuttles to prevent them from burning up)
• Cold Resistant

Powers:

• Super Speed
• Enhanced Stamina
• Accelerated Healing
• Can always eat more food (but the speed force protects him from starvation)
• Time Travel

Other Abilities:

• Viola
• Fluent in Sign Language (Gorilla Sign Language)
• Web Design
• Very Competitive Ice Dancer

Canon:

• Barry states that when running he can conduct a "significant electrical current"
• Instinctively phases through a wall to avoid crashing into it (not an ability he's shown to be competent with or even mentioned)
• Knightmare Barry sends a message to 2016 Bruce about how to stop the Knightmare world from coming to be (likely through the use of cosmic treadmill)
• Channels lightning through himself to charge up the Motherbox and revive Superman
• Manages to communicate with CW The Flash, despite them being in entirely separate Multiverses

Snyder Cut:

• Survives the destruction of Earth by entering the speed force
• Reverses Time by going MFTL
• Speed Healing

Canon:

• Avoids Superman's blows while the rest of the Justice League are statued
• Matches Clark's Flight Speed in a race
• Views a Batarang in slow-motion
• Draws on an inmate's face with a pen so fast that he doesn't notice
• Blitzes a thief and returns back to where he was fast enough to catch his milk bottle
• Dodges Plasma Blasts from a Parademon and then pushes it through a door
• The Flash can punch at the speed of light but is afraid to
• Stated to be able to run at the Speed of Light in a JL Promo Advert
• Stated as Light Speed in his Suicide Squad Fact File

Snyder Cut:

• Barry near-statues his surroundings to save Iris
• Runs so fast he appears to teleport
• Blitzes a Parademon
• Saves STAR Labs employees from falling rubble, creates multiple after-images in the process
• Circles the city where Steppenwolf is situated at an extremely fast rate
• Runs at a speed "far beyond the Speed of Light" to reverse time

Canon:

• The Flash can punch at the speed of light but is afraid to
• Pushes a car a hundreds of meters forward
• Explodes Parademons with his blitz
• Explodes dozens more Parademons

Snyder Cut:

• Pushes a Parademon through a door
• "Infinite-mass punch" - should have an adaptation of this iconic Flash ability, considering he can go FTL now (mass increases due to laws of relativity)

Canon:

• Survives an 'explosive' attack from Superman with no lasting injuries
• Survives being tossed into a pillar by Steppenwolf with no lasting injuries
• Gets grazed on the leg by a Parademon Plasma Blast (though it stops him from using his super speed)

Snyder Cut:

• Gets back up after a Parademon blast
• Speed Healing
• Not really a durability feat, but can enter the speed force to survive the destruction of Earth