ColEm is a ColecoVision emulator designed for Android devices. It allows users to play classic Coleco games on their phones or tablets using various input methods like Bluetooth gamepads, USB joysticks, and virtual gamepads.

The emulator is optimized for speed and provides full-screen portrait or landscape mode emulation with options for simulating TV scanlines and fuzzy TV display, giving players an authentic retro gaming experience. Users can save their progress and restart from the same point if they get defeated. Additionally, ColEm enables players to record ColecoVision music to MIDI files, which can be used as ringtones on their devices. The app comes in both free and paid versions, with the paid version (ColEm Deluxe) offering additional features such as better joystick support, network play, and the ability to share saved game play with others. However, the emulator itself does not include any games, and users need to provide their own legally owned game files to run on ColEm.