Love the Sigmarine!
Your diorama looks excellent too, and your wips have been a solid inspiration.
I have some crushing crit for your diorama though - please don't hurt me....
I think the texture of the base is too similar throughout. I reckon a smooth, cleaner ground (either side) will make your models stand out a lot more, and give some relief to the eye.
Horribly, I think the river is slightly jarring - both visually and maybe thematically (aaaaarrgh!). If you're going for dark, misty coldness, I think a deep, dark, dank smoother river/stream would fit better (you could still use the ice in the water, maybe cracking where feet have been?). Unfortunately the combination of the river flowing left to right, and the river width going from right to left feels a little weird (if that makes sense?) the duck is brilliant btw, and I reckon Kretchers animal trappedbetweenthetwo suggestion is a cracker! I realise the amount of time and effort put into the river must've been huge, so it's a no brainer to keep it and just adjust for next time.
Man, I feel like the worst person ever after this post...