The announcement came during a 100-minute livestream. As announced, the Mega Drive Mini 2 will feature up to 50 games, including some Mega CD titles which are just slightly more than the 42 of the original Mega Drive Mini. Although for now, only 11 of them have been confirmed:

Bonanza Bros.Fantasy ZoneMagical Tarurūto-kunMansion of Hidden SoulsPopful MailShining Force CDShining in the DarknessSilpheedSonic CDThunder Force IVVirtua Racing

It’s also worth noting that for the original Mega Drive Mini, the games that were included would differ depending on which region the mini console was made for. At the moment, there’s no indication of if the Mega Drive Mini 2 will have something similar going on, at least not yet. The Sega Mega Drive Mini 2 will be available on 27 October 2022 for a price of JPY9980 (~RM335). It only comes with one six-button controller, but Sega says you can buy more for JPY2500 (~RM84) each. On the day of release, a miniature Mega CD attachment will also be made available to go with the Mega Drive Mini 2. This will cost an additional JPY4500 (~RM151). It will also have a spacer to allow the first Mega Drive Mini, which is larger than the sequel, to be mounted on as well. All that being said, there’s still no word on when the Sega Mega Drive Mini 2 will be available outside of Japan. Though considering the first one was also made available elsewhere, so it’s likely this sequel will too. (Source: Sega / YouTube [1], [2])

Sega Announces Mega Drive Mini 2  Priced Around RM335 - 98Sega Announces Mega Drive Mini 2  Priced Around RM335 - 19Sega Announces Mega Drive Mini 2  Priced Around RM335 - 52