I think it's really good. Been playing it only for an hour or so last night, so I can't really give you too much feedback yet, but here's some criticism:
1.) The range finder on the T-26 doesn't seem to work. If you raise the distance, the shell falls on the ground right in front of you.
2.) If someone deploys a mortar on a bumpy surface (in a foxhole for example), the mortar and the mortarman might "separate", it looks pretty weird.
3.) If the mortar support guy gets close to the mortar operator, it should say "press G to supply shells", or something like that. Would be a bit clearer.
4.) The weapon handling feels a bit "stiff", not as fluent as stock RO. Also, I had a lot of trouble hitting someone with the new Steyr rifle. A new weapon in RO takes a considerable time of getting used to though, so it could be just me.
That's it for now, other than that it's great. Still haven't gotten the chance to play with the mortars.
The level design is awesome by the way!