The point about the head shape is that they tend to have a valley, rather than an extrusion in the forehead according to pretty much all the reference material you can find online:
Still, if you prefer it this way, it's your model, so do what you like and enjoy it!
The render shows some more problems with the tentacles - looks like overlapping faces. Again, it's not bad for a first go, so perhaps try it again and see how you can improve it as you go
