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Do old leapster cartridges work on this?
The LeapPad1 and LeapPad2 work with the entire Leapster Explorer library of game cartridges and digital apps, with the exception of the Photo Mania app.  Game cartridges labeled Leapster Explorer, LeapFrog Explorer, Explorer or LeapPad Explorer will work with the LeapPad.  

Some digital apps are only designed for LeapPad1 and LeapPad2 and cannot be used with Leapster Explorer - these  apps are designed to take advantage of the LeapPad's larger screen, motion sensor and microphone and so are not able to be played on Leapster Explorer.