Hungry Siberian Hippos, fun and well fleshed out.....
for every extraplanar uber beast we should have ten of these quasi-mundane but developed creatures that suggests to the characters that the fantasy world is more than just string of encounters, singular forces (light, darkness, evil, nothingness etc) and quest items, but a deep and complex world.
A nice enough straight forward plot, nothing really wrong with it, but nothing to really draw you in. A reasonable honest group of PCs could get through this whole adventure with two roll playing encounters and a spot/search check. Getting the item out could prove a challenge, but an experinced group of gamers should move straight through that.
I like this one, nice lead in, fun plot-going to planet with that kind of write up will certainly get the PCs interested-classic drama, not a lot of character details but that just makes things more flexable and there is actually a lot detail here.
The only I would ask for would be a little more description of the Sneel themselves and what their home world might look and feel like.