Played on PSP, not emulator.
FPS can drop when theres allot going on.

Rebind your controls !!
If you're not on a PSP but on PPSSPP or Vita you can just play with the "Dual Stick Mod"

Soundtrack is unexpectedly good, this is my first ever Armored Core game so I didn't know what to expect.

You play through various missions and try to make your AC better and better, sometimes you fail a mission with your "main" AC and have to switch to an AC that works with water combat etc.

Story is told through short dialogues in the missions and the mail system. I'm usually not a fan of mail systems but I thought the story telling worked pretty well.

Arena makes for some nice money.

Will check out the other games.