So i ran into this problem with my copy of Illusion of time. I played it a year or two ago without problem and haven't touched it since.
The graphics are all messed up, parts of sprites and the backgrounds are all jumbled together all over the screen. Also when in the inventory all the items are also messed up, but exiting and re-entering the menu a couple of times fixes this for some reason.
Of all the games i tried this is the only game that has this problem. And it's just in certain parts. All the interior areas of the incan temple is fine, but the cliffside with the big faces are all messed up, so are all the towns and interiors of the houses.
I tried cleaning the cartridge with some rubbing alcohol but it didn't help. Any idea of what could be the problem and if it's fixable?