Doom probably isn't workable on the RS-90 due to the lack of buttons, a port would need to be tailored to the system and use button combinations like the GBA version. Mapping weapon switching to "R+L+Up/Down and the B button to both run and use would sort it.
GPD Win, GPD XD 64gb, PlayGo, RS-90, 3DS XL, DSi XL, GBA SP, GBBC Clone, Gameboy Pocket c/w screen mod, PSP Go
Medion Erazer, Toshiba Z20t, Dell Mini 9, Psion 5MX
Tons of other old laptops and tablets.....