every emulator i've played on my gp32 is excellent so thats a damn hard decision
Fgen faves are Ghouls and Ghosts, Columns, Revenge of Shinobi
Pc Engine - Space Harrier, Gradius, Salamander, R-Type, SideArms
Speccy - Knight Lore, Zynaps, RanaRama
C64 - Armalyte
Snes - Any Mario Game
Doom will...