Exposure on the tarantula (SP) looks good and the light is very even over the body. You also focused on the right part of the bug - the eyes - which is always key to the shot. All in all I rather like it (even though I hate spiders - especially big ones!)
The snails are showing overexopsure in the upper areas which is distracting for the overall shot and drawing attention away from the bugs. I think its an interesting shot with some good composition as you have two insect types showing with the slug approaching the snails - maybe play around with editing and try to reduce the brightness and glare from those upper areas