recently i worked on remake of DOS remake of Konami's Knightmare game.
the game is playable now, it has music from original MSX Knightmare, and
sfx/gfx/levels from DOS remake. it is written in D, of course, and it is
FOSS. you can find the sources here.
as usual, you'll need my IV modules, and Adam's ARSD modules.
the code won't work on 64-bit arches, tho (due to some bugs in sdpy/iv).
but it can be compiled for 32-bit GNU/Linux, and 32-bit windows.
here is windows binary for those who cannot (or don't want to) build the
WARNING! the code is a partial port of old DOS turbo pascal sources, so it
is *very* far from something even remotely sane.
it is not polished yet, but that should not stop you! play this excellent
classic shooter while it is hot! ;-)
some tech info: arsd.simpledisplay is used for video (with OpenGL backend),
arsd.simplesound for audio (with my AY-8910 emulator), iv.vfs for VFS
support. as the game designed for 20 FPS, i didn't bother avoiding GC (that
is, the engine allocates like crazy).
enjoy, and happy hacking!