The Jump action can be executed using Space key (keyboard) or A button (gamepad). Jump can be performed twice to jump higher.
Some skills can be performed airborne. For example, Angela is able to use Magic Missile while jumping. All characters have the passive skill Mid Air Dash which allows them to dash while in mid air. Altitude is lost with each dash, albeit at a slower rate than without dashing.
Some dungeons require jumping to safely proceed. For example, Public Baths features sections with spinning spike logs that damage characters and increase "Hit Count" upon contact.
Jumping is used in certain quests, such as Bring the Balloons, which require jumping and attacking to obtain Balloons.