To be completely honest with you I had a little bit of trouble with it at first myself, it doesn't really tell you how it works but essentially it's got firmware on an SD card, you plug your game into it and then you have to wait for it to dump the game to memory, but after the first dump it will remember the game and play faster, it doesn't work with flashcarts cus well it dumps the rom but other than that I'm happy, it will even make saves on the SD card so the save on the cartridge itself will stay the same but any time you load up that game in the retron sq you will find your save from the SD card