Two PC Engine game series are revived on Sony PSP one of them is Tengai Makyou Collection, one of the classic RPG games and the other is Galaxy Fraulein Yuna, an ancestor of bishojo games.
Galaxy Fraulein Yuna is a digital comic that portrays Yuna's growth from an ordinary teenager to the messaiah of light. Aside from the heroine, the rest of the cast, including enemies are all designed as pretty girls. The collection also contains the second installment Yuna 2, which features two new characters Yuri and Erika 7 and a red hot battle system.
The third game in the collection is Galaxy policewoman Sapphire which switches the spotlight from Yuna to a group of four powerful girls. Instead of using the battle system in the old games, Sapphire is a shooter. Take down terrorists and criminals as a cute police officer.
Sapphire! I bought this collection solely for the inclusion of the port of Sapphire, a rare shmup from the PC Engine. I've barely touched the other two included games, and in all honesty, I don't really need to. The entry price for this collection is worth it for Sapphire alone. Unless you have a PC Engine, this is the only (legal) way to play Sapphire.
And let me say - it's a doozy. Probably one of the most difficult shmups I've ever played. Here's a tip - start out on the easy setting. Switch to Normal once you have a grip on the game. The emulation itself seems excellent to me, though I've never played the PC Engine version of the game, so I can't really compare. It has 3 screen options, native res, zoom (stretched to top and bottom in 4:3), and zoom/stretched 16:9, which fills the entire PSP screen. The native res option, while the smallest, looks the nicest, likely a 1:1 pixel ratio with the original.