Can anyone tell me some PSP top-down or side scrolling shooters that are like Ikaruga, R-Type etc? I couldn't find any :(

Your best bet for any top-down or side scrolling shooters is to hack your PSP and run emulators to play older console ones. Or Japanese ones.

yeah, there are barely any shooters like that on the PSP.

I'll name you some good games when I get home.

Alright, thanks, I'll look for some roms.