The engine is GB Studio! its for making Gameboy and GB Color games. The jitter you mean is the camera shake when you get hit? its a feature in the program, i can control how long it last and the intensity of the shakes. but how it does it code wise, i dont know.
The program is doing most of the heavy lifting, it handles a lot of the code, and you can add your own. My coding is very limited; thats why i used this engine. Im sorry if you were looking for a coding answer.