Grave Filler is a whimsical ball drop puzzle game designed for Windows users, where players assist the character Batbo in filling graves during his night shift. The gameplay revolves around dropping various items like rocks, dirt, bugs, and mushrooms into graves, which then merge to create larger treasures. The game features a score multiplier for consecutive merges, encouraging players to strategize their moves for maximum points.

In addition to the core mechanics, Grave Filler offers unlockable features that enhance gameplay, such as swapping incoming balls and drops with special effects. Players can also customize Batbo's appearance with cute outfits, adding a personal touch to the experience. The game includes a personal high score board, allowing players to track their progress and achievements.