there's a whole market for these pocket sized (and non pocket) emulators. My MM+ w onion os is great for gba games. been grinding out the battle network series and this just lets pick up and go.
I recommend Retro Game Corps the most for recommending these types of systems.
Holy shit boktai was kojima?! Only reason i about this series was the crossover chips and and endgame quest in MMBN4 and on. Super cool and unique concept with the solar panel stuff.