Thanks to it being based off Visual Boy Advance, the emulator is very highly compatible. Also thanks to its base it is also a very accurate emulator.
The emulator provides a wide support for memory bank controller, also including support for the Game Boy Camera. Included along with the Game Boy link emulation, the emulator also provides support for IR link, but is rather imperfect. GEST like many emulators has not seen any signs of development for some years, the final release was in 2011.