BZZT wrong
Computing is not just the code, its the design. GameMaker, The Games Factory/Multimedia Fusion et al are extremely powerful design tools. I do not blame him for using a point and click game engine to realise his ideas quickly, coding a sprite engine instead is just added hassle.
Sigh... I wish programmers would just use whatever is best for the job instead of trying to do everything the hard way. Speed is not an issue for a 2D game on modern PCs. Portability is not an issue for him. Flexibility is not an issue for this rather simplistic game, no 3D or networking or anything special. So what arguments are there for NOT using it? The fact that some people think that it's a 'joke' is pretty lame when most of them are using DirectX or OpenGL with GLUT instead of coding their own libraries from scratch, or using bytecode instead of using 'wimpy' compilers that do the job for them but without as much optimisation.