Aetherbyte has released a free shmup, NANTETTATTE ENGINE starring ROM², to celebrate the fact that the PC Engine console (not even well known under its western moniker TurboGrafx-16) has turned 30.
As a shmup player you really should get a PC Engine if you don't already have one, it has a fantastic library of shooting games. Make sure to get a variant with a CD-ROM, it's worth it.
You're going to need something like the Turbo EverDrive to play the game.
Here's a shot my own gorgeous unit, complete with IFU, CD-ROM and Everdrive: