Some shots or cuts may be slightly longer or arranged differently. The opening sequence (Barry as a forensic scientist vs. the final reveal of the Reverse-Flash’s yellow suit) might be paced differently.
The most obvious difference. Many of the speedster effects (lightning trails, the red blur, phasing through walls) are either incomplete, in wireframe/gray-box form, or replaced with temporary markers. For example, Barry’s first run after being struck by lightning might show a simple motion blur instead of the iconic orange-red lightning. the flash s01e01 workprint
That is an interesting find. The workprint for The Flash season 1, episode 1 ("City of Heroes") is a known artifact among fans of the Arrowverse. Some shots or cuts may be slightly longer
Here’s what makes it significant: