Jump in the Line is a three-dimensional endless dash-style runner game. A player directs the movement of a red block outlined in glowing white along lines made of other blocks. The player's only task is to keep the block from falling off the main line. If it falls through the air below the bottommost line, it breaks apart into pixels.
The player can only direct the block to roll forward, jump and slow to a stop. If they combine the rolling and jumping actions with enough momentum, they can direct the block to roll forward in the air during a jump as well.
Jump in the Line presents the player and their block with a lot of challenges, including block stairs, massive sloping lines that create ramps, lines hanging mid-air and gaps between lines. The player can overcome these obstacles by timing their control of the block so that it rolls faster until it's bouncing enough to gain even more speed and forward momentum.
The player also keeps the block from falling by using the jump action to bounce it high in the air at the exact moment when a part of the line below it starts to disappear or when it becomes stuck against another block.