These particular EXEs are free of any malicious code: there are only 16 bytes changed (addresses are valid for 1.05 Darkstone.exe):
005e03h-005e04h, 00b3a2h-00b3a3h, 00b464h-00b465h and 06e86ah-06e86bh: X-resolution (2 bytes, big endian), eg. for 1920 it would be 80h 07h;
005e0bh-005e0ch, 00b392h-00b393h, 00b45ah-00b45bh and 06e865h-06e866h: Y-resolution, eg. for 1200 it would be b0h 04h.
Actually, there's much more info at WSGF: http://www.wsgf.org/dr/darkstone/en
(patched EXEs for 1280x720, 1280x1024, 1360x768, 1680x1050, 1920x1080, 2560x1080, 3440x1440, 4800x900, 5760x1080 included).