How to disable vertical mouse movement in DOS
Since the vast majority of DOS first person shooters did not feature true 3D environments, the vertical mouse axis was utilized to move the character back and forward instead of looking up and down, a standard which was set by Quake in 1996. For players not used to utilizing the mouse to move, this can be irritating, especially since it is usally not possible to turn this behavior off in the configuration file. One possible solution exists in the form of NOVERT (http://www.doomworld.com/idgames/index.php?id=12039) by Istvan Pataki, which is a DOS TSR that works both in real DOS and DOSBox.
Unfortunately, in Blake Stone, Wolfenstein 3D and possibly other games as well, this causes the game to think that the up arrow key is constantly pressed, making the game unplayable. NOVERT can be hexedited to fix this:
1. Open up the Windows command prompt, change to the folder where the file is located.
2. Type "debug novert.com", hit enter.
3. Type "e131", hit enter. After it stopped at 33. type "b2", then hit the space bar. After it shows "D2." type "64" and hit the space bar, then enter. Then type "w" and enter. Finally type "q" and enter.
It should look like this:
140D:0131 33.b2 D2.64 CF.
Writing 0018B bytes
The fix was discovered here: http://www.gog.com/forum/blake_stone_series/mouse_config_q