Happy Filled Glass is a physics-based logic-puzzle game that features anthropomorphic glasses that the player must fill with bright blue water. The player performs this task by drawing one or more lines to create channels to direct the water from a dispenser into each glass. They must also try to collect three gold stars per level.
The game features 30 levels. Each one displays the glass near the bottom of the screen in front of a graph paper background with a water dispenser somewhere above it. The game places colorful obstacles between the dispenser and the glass, such as circular objects and straight boards.
The player draws the channels using a pencil. That said, the game limits the amount of lead the player can use to draw lines. A green horizontal bar near the top of the screen represents the stars that they can achieve in a level. Every time the player draws a line, some of the green color disappears, and they lose the opportunity to collect one or more stars.
Happy Filled Glass provides the player with unlimited hints that reveal the precise lines the player needs to draw (position and length) on the graph paper.
