There are currently fifty-nine cutscenes that can be viewed in the cutscene gallery.
The story of Run 3 is primarily told in the form of cutscenes. After beating certain levels, a cutscene will begin to play, usually depicting an interaction between two or more of the characters that either allows the player to have a better understanding of their personalities or furthers the plot.
Before cutscenes were implemented into Run 3, an "End of the Line" sign was the only reward for finishing a tunnel. After several updates, cutscenes were added, replacing the temporary signs at the end of the tunnels. At this point, every completed tunnel in the game has at least one cutscene at the end of it; however, several have other cutscenes that appear after levels mid-way through the tunnel as well.
Many cutscenes are encountered in the minigames. Some cutscenes are only unlocked after meeting a certain standard, such as the cutscene Planet Missing, which requires fifty levels beaten. You can also use 15 power cells to unlock the cutscene Batteries in the Shop.
Once in the cutscene gallery, it is a simple matter to view and navigate through the many cutscenes. The small arrow icon in the bottom right and left corners of the screen make it easy to scroll through the cutscenes quickly, and the home button in the top left corner allows you to return to the Main Menu at any time. Alternate keyboard controls can be used for both of these if playing on a computer; arrow keys for scrolling and escape key for the menu. The mouse can also be used to scroll by dragging the screen to either side.
To view individual cutscenes, simply click or tap on the cutscene's icon when it appears on the screen. Larger icons mean that the cutscenes are more important to the plot; smaller ones are more like side tangents or comedic relief.