Yep, I recommend getting something like an EZ flash so you can play .gb rom files on the Pocket. You don't have to get one but you will be locking yourself out of the vast majority of classic and homebrew GB games without one. And you will have a far better chance of playing these published GB Studio games on your pocket rather than hoping to see the devs debug a migrated GB Studio game just to output a .pocket file. Although you should make sure your flash cart of choice will work with the pocket before you purchase.