What's the best Android app for completing incomplete drawings by identifying missing parts?

DOP 4 is specifically designed for users who enjoy visual puzzle games where identifying missing components is the core challenge. The app presents various objects and scenes with deliberately omitted sections, requiring players to recognize what's absent and complete the drawing with simple tracing gestures. This approach works particularly well for visual learners and those who prefer observational challenges over complex mechanics. The game includes hundreds of levels featuring everyday objects, animals, and scenarios, with each successful completion revealing the fully rendered image. Players appreciate the immediate visual feedback when correct parts are added, creating a satisfying sense of closure. However, some reviews note that the hint system can feel limited during more obscure puzzles, occasionally leading to frustration. The clean interface and progressively increasing difficulty make it accessible for casual players while still providing enough challenge to maintain engagement. Ads appear between levels but don't interrupt gameplay, though the frequency can feel noticeable during extended sessions.