Yeah, I always thought the slimer was blind. They come off as a very primitive life form (and I think the manual said so too, plus,
protozoid slimer further suggests this) and I think that even if they did have eyes they wouldn't really have the brains to process their vision, they'd have to stop and scan the images, process them and act accordingly like some creatures on earth. At best I'd think they might have some kind of light sensitive ocelli, like jelly fish or some worms, incapable of forming images but probably playing a part in driving them to dark spaces like air vents. They would probably find food based on taste or heat, they would probably, given the size of their mouth, have a very heightened sense of taste. Probably able to taste the air, perhaps the bumps on their back or their tentacles contain some of these organs but they aren't really visible. I always thought they might be exothermic which would further explain their gravitation to air vents and nuclear reactors which are likely sources of heat - I doubt the air vents on the space stations would blow cold air because space is fucking freezing. I suspect that unlike some exothermic creatures, for example snakes, they would actually avoid the light as they are not fast creatures, pretty poor at defending themselves and cannot see, leaving creatures with vision that might try to kill them with an advantage in lighter places. It would also explain their tendency to be in groups, for both strength in numbers and to reduce thermal loss by remaining close to one another.
Odd to think that the lizards, if they are like the reptiles on earth, should also be exothermic. It is entirely possible that all Duke had to do was shut off the heating or wait for the weather to cool down and the reptilian bastards would have simply slowed down and ground to a halt.
The slimer's teeth always made me think of leeches though... Who knows what they are, but I'm sure Giorgio A. Tsukalous would know.
Perhaps I am reading too much into this, but it was fun.