@Axel yup that's been my experience. Using a Galaxy S8+ and Altered Beasts runs a bit janky. Don't know why Sega doesn't just partner with one of the emulator creators and use it as a platform to sell their old games.
I'm a little disappointed they aren't offering a Sega Forever app that we can use to launch the games from. For now, you have to search for each game on the store and download them individually.