Okay so the games that don't work that I have tested recently are:
Squares - PSPlus
Cosmic Star Heroin - Purchased
Civ Rev 2 - Purchased
Letter Quest - PSPlus
Exile's End - PSPlus
Actual Sunlight - PSPlus
Burly Men at Sea - PSPlus
Sky Force Anniversery - PSPlus
Most of the games on my Vita are legit and obviously I haven't tried nearly every game. I've tried reinstalling the games and sometimes pirating them via PKGj but to no avail
I have the key file for reFOOD
I have high firmware games installed that do work and some of the games that don't work should work on my firmware without it I think.
Edit: I could try installing compat packs but the games don't launch at all. I've tried that before and it hasn't worked but I could try it again. Should I post my Tai Config to see if anyone can spot obvious issues there?