hexsector
A boot sector sized (510 byte) clone of the game Hexcells. Cheap as chips, great puzzle game - pick it up if you haven't already.
The source code of the game (main.asm) is extensively commented: please check it out! I've tried to explain why things are written how they are (probably optimisation) and it should be readable if you're semi-familiar with x86 assembly but rusty on real-mode shenanigans.
Left: game grid, dots in grey cells indicate neighbour count
Right: mistakes counter
Building
Run make inside the repository directory. This will require nasm and python to be installed, and I can't guarantee it'll work on a non-Linux box.
floppy.img will be created - this is a raw 3½" floppy disk image that can be used in QEMU, Bochs, VirtualBox (may need to be renamed to floppy.dsk), VMware, or even put onto a real floppy (?).
To change maps, change the value loaded into cl before the int 0x13 call in main.asm from between 0x0002 and 0x0005. Each map is stored as successive sectors on the disk after the boot sector.
Controls
Use WSAD to move the cursor (green outlined hexagon) over the cell you want to guess/discover. Press O to attempt to uncover a blue cell (left click in the original game) or P to attempt to uncover a grey cell (right click in the original game).
Running
QEMU: qemu-system-i386 -drive file=floppy.img,format=raw,index=0,if=floppy
Bochs bochsrc.txt: line 1 = floppya: 1_44=floppy.img,status=inserted, line 2 = boot: floppy, run bochs -qf bochsrc.txt
VirtualBox: rename floppy.img to floppy.dsk, assign as media for floppy drive