Real gameboy, but with an IPS screen mod, shell replacement too as the IPS screens are a little larger than the original requiring some cutting if you don’t. I did the same to my OG 1998 atomic purple GBC.
Red and Blue predated the GBC but if you played it on one it would tint each area a different colour based on the area. However it wasn't until Gold and silver that more varied pallets would be used. This game has an IPS patch applied to it to give it similar colours.