The trouble is the standard expected of Amiga games is a lot higher, and therefore a lot more involved than that of ZX games (great though they are).
Yes, but there is also the hardware challenge too. The Amiga makes it very easy to use a single bitplane (line 1 follows line 0 etc.), whereas the Spectrum does it a little differently (e.g. line 0, then line 7, then line 15, line 23, line 31, line 39, line 47, line 55 and then line 1, line 8 etc.).
You only have a single bitplane to worry about, plus the 2 colours per 8x8 pixel area to work on (or overcome if you know how). I have a handful of cool demo's by Andy Severne (&e7) which I absolutely loved on the Spectrum.
Regards,
Lonewolf10