Short answers, pulled from the story.
M2 is a Japanese video game developer and publisher best known for emulating and re-releasing classic games, including Sega Ages titles for Nintendo Switch, the 3D Classics series for Nintendo 3DS, Virtual Console titles for Nintendo systems, and their ShotTriggers label for classic shoot-'em-up releases.
M2 created three original WiiWare games for Konami under the ReBirth label: Gradius ReBirth in 2008, Castlevania: The Adventure ReBirth in 2009, and Contra ReBirth in 2009. Each was a new game in a classic Konami franchise rather than a port or direct remake.
M2 holds the rights to the Aleste series (except M.U.S.H.A., which is owned by Sega), all SPS games and software, and all NEC Avenue and NEC Interchannel games on TurboGrafx-16 and its variants. Those rights were previously held by a company called Lightweight.
ShotTriggers is M2's dedicated label for re-releasing classic shoot-'em-up (STG) games. It was built on M2's work porting Cave titles such as Mushihimesama Futari, Ketsui, Dangun Feveron, and ESP Ra.De. Psi to modern platforms, and continues with releases like DoDonPachi DaiOuJou Re:Incarnation in 2023.
Yes. M2 contributed to both the Sega Genesis Mini and the Sega Genesis Mini 2, as well as the TurboGrafx-16 Mini and the Sega Game Gear Micro. The studio's long history emulating Mega Drive hardware made it a key partner for those dedicated mini-console projects.
M2 developed Fossil Fighters and Fossil Fighters: Champions for Nintendo DS, the three Konami ReBirth games for WiiWare, GG Aleste 3 for Nintendo Switch and PlayStation 4 in 2020, Tokyo School Life in 2019, and the arcade title Senxin Aleste in 2021, among other original projects.