I haven't ever contributed much to Amiga unfortunately. not because I don't want to, I really would.
Even tho I am very good at getting the most out of C64 basic (that's what I grew up with), and not too bad with the Spectrum Arcade Game Designer, I have never been able to progress to any language beyond basic even on the 8 bits so I pretty much give up before I try on the 16 bit machines.
I can knock up something reasonable in AGD in a few days for the spectrum, but even then I stick to more Atari 2600 type graphics and keep things simple. I am guessing even getting to grips with the bare basics of AMOS or Blitz is going to take longer than one of these games takes me complete. Unfortunately with work and family commitments I don't think I would really ever get anywhere near releasing even something simple.
I wouldn't even know which one I ought to start investing my time in, Blitz or AMOS?