If you run La-Mulana (2006) on Windows Vista or newer, it does not render text on the MSX console window. This renders the game basically unplayable, as you cannot read tablets.
You can work around the bug by editing the font.bmp image. The fixed image is provided herein.
The font file is located at LA-MULANA/graphics/font.bmp. The workaround is to edit the image so that the font is rendered in a color other than hexadecimal FFFFFF white; even an off-white color like FFFFFE will do. The difference is imperceptible to the human eye. It used to be possible to find the modified font.bmp file on the Internet, but I could not find it anywhere, so I was forced to fix the file myself. I found it in PNG format, but that still left me with the task of doing the conversion myself.
My attempt to edit the image in GIMP resulted in the game crashing immediately upon startup. MS Paint also failed. Clearly, these programs made other changes to the file that the game was unable to deal with. I found directions on how to make the change using Photoshop, but I do not have Photoshop.
So I opened up the bitmap in the hex editor XVI32 and looked up the bitmap file format specification. I found that the bitmap had an 8-bit palette with 256 colors, even though it was a simple black-and-white image. I looked at the pixel data and saw that the image was indeed composed of two colors; hexadecimal 11 and 1F. Looking up those entries in the palette, I saw that color 11 was 000000 black and that color 1F was FFFFFF white. I then edited that entry in the palette to FFFFFE. I opened up the game, and the fix worked perfectly.
I also applied the change to the original Japanese version of the game.
Here are the images, in bitmap format so you do not have to convert it. You can simply put it into the graphics directory and it will work.
English version (Aeon Genesis English fan translation patch):
This bug does not affect the recently-released remake of the game.