@itix
Well, they are poor in hindsight, but at the time, all amiga doom clones were hell bent on using chunky copperscreen trickery for their display. The 2x2 pixels were an artifact of that. It was also designed to work in a 2MB chip only A1200, so the visuals are bound to be a bit stunted.
However, consider also that this game ran in 4096 colours (12 bit RGB as opposed to 256 colours), complete with goraud shading, transparent, tinted and bumpmapped water at an playable speed on a basic A1200 with 2Mb additional fast RAM. With any kind of accelerator, it gets very smooth.
Not a bad achievement ;-)
AB3D2 had much more impressive visuals. 1x1 pixels in 256 colours, goraud shading, realtime lighting, colour dithering (I kid you not - view on a monitor) bumpmapped lightsourcable sprites, different types of transparency, vector objects etc. It was, IMHO considerably more advanced than either AB3D or DooM. It also suffered performance wise as a result.