Lovely work on this piece Yury, congrats!
Some comments: firstly, what date is this intended to be?
The face is wonderfully done, in case this was not intentional the left cheekbone is a little less pronounced than the right.
The texture of the fur pelt doesn't work for me. It seems to be very consistently done but it's a bit stylised, when compared with the beard and hair texture for example which are more naturalistic.
The mail texture looks excellent, if perhaps a little oversize - period mail often had very small rings. The front of the chest seems quite flat, especially as the bust appears to be posed leaning forwards slightly; it's not obvious from illustrations but underneath the mail brynja it is likely they wore a padded garment of some kind to help soften the impact of blows and one of these would add a lot of bulk to the chest area (at least a full finger's thickness, possibly a lot thicker overall or in parts).
Is the helmet based on the one from Gjermundbu? It's hard to judge from the photos but it may be a little small. Either a padded cap or a suspended leather lining would be underneath the helmet (possibly both!) so that the force of a blow isn't transmitted directly to the skull. In addition there might also need to be room for a mail coif if the wearer could afford one.This means that in practice helmets would sit out from the skull more than we're used to seeing (in reconstructions and illustrations, not just in movies).
Einion