Hi Methuselas, et al.
I wonder if we could get the author to release the sources.
I'm pretty sure this question has been asked before, and Alastair no longer has either his machines or the source. (Someone please correct me if I'm wrong).
Looking at a dissassembly of the executable, it does indeed look like AmosPro code, as SamuraiCrow mentioned. (The startup code looks for AmosPro gui.library).
A lot of register-relative code, which can make it a little difficult to decipher.
Having said that, probably wouldn't be fantastically difficult to reverse engineer though if there was sufficient interest?
Cheers,
Red