Yeah... I registered my copy of Pontifex II. :-) One of very few shareware games I've ever done that for. (MegaBall, perhaps being one of the only other few I can think of offhand!)
Anyhow, Pontifex (formerly known as "Bridge Builder") is really a blast. Or, perhaps, a splash, if you mis-construct things! My girlfriend's little brother has a ball deleting crucial structural pieces from my designs and then watching them crumble into the water as so many chunks of twisted metal debris.
I am a little puzzled why it's under "Amiga gaming"? Is there a Linux PPC version in addition to the Windows and Linux x86 versions?
