I've bought a copy of Iron Dragon for the PC - I can even find the license key in my ancient google mail. It was published by http://www.antigravitybox.com/ and the game's website is http://www.irondragon.org/

I don't see too much of a difference other than Steam has more proven longevity - even if the developers that sold games on Steam don't. I can still download Dungeons of Dreadmor from Steam even though the company appears to have disappeared in 2016.