I don't see where you're drawing your conclusions from. Donkey Kong Country for the GBC is 4 MB, but that doesn't mean it's a broken game. Also, there's nothing wrong with it being 2.7 MB when compressed and 4 MB when not compressed as that's the very definition of compression.
GBC games do not contain much trimmable data. Goomba Color supports slightly trimmed/compressed roms, but only with its special trimming tool. These games would not run in Lameboy.
More than likely, the problem is that you believe that Lameboy has perfect compatibility when it doesn't. This game may just not work properly in the emulator for the time being. If you have a slot-2 device, you can try using Goomba Color, but that's the only real option you have.