Happy Filled Glass 2 is the next installment of the Happy Filled Glass physics-based logic puzzle series. The player's primary goal is to fill anthropomorphic glasses with water from dispensers across 45 levels. Their secondary goal is to complete this feat without losing three gold stars given to them at the start of each level.
Each level features a glass on a green shelf at the bottom of a wall covered with graph paper and a gray dispenser marked with a white arrow mounted somewhere near the top of the screen above one or more obstacles, such as stationary boards and walls, rolling balls and dropping shelves. The player must also deal intermittently with rectangular and round heating elements that can turn the water into steam and shelves marked with arrows that speed up the flow of the water.
The player fills each glass by directing the water using barriers and channels drawn with a pencil. Yet, the player loses stars when they use the pencil. When they draw a line, a yellow horizontal bar above the playfield that represents the stars disappears bit by bit.
Happy Filled Glass 2 offers free hints that reveal the best positions and lengths of lines to use to save the gold stars. That said, no matter the star count, the player wins a level as long as they fill the glass. They then receive a burst of blue and yellow stars near the glass, and colorful confetti floats down from above it.