1.Interception can be performed only after a group of ships came into the sea zone, or it is also possible if ships are just present in the seazone, without moving?
For example: there is no sea movement in German Turn, but German ships are presents in the V zone, along with british ships. Do the Germans can intercept british ships, and - if they decided not to intercept - Royal Navy has its chance to do it, as a 'defender’?
Interception can be made when ships are present without moving by the attacking player only (this ends movement for participating ships).
The defender can only react to the movement of enemy ships or task forces.
2. It's written on Allied Submarines cards: "Sinks a German reinforcement". Does it means that I can sink ALL german reinforcements, that landed in a specific area (could be even a few battalions!), or only ONE battalion?
Only one German battalion.
3. Do the Germans need to have some ships in I-II seazone, to land battalions?
4. The Alllied Coastal Transport card could be used to evacuate only 'defeated' battalions, or maybe also those, who were simply forced to retreat?
I think that is a fair "house rule" although it was not written like that. It was written as it is mainly to keep the explanation simple.
5. Am I right while intepreting victory conditions in that way?:
Clear victory - in fact 'instant victory', triggered immediately when at least one of the conditions enumerated below is met:
1.Norway and The Allies defeat all German battalions on the board
2.Germany defeats all Norwegian and Allied battalions
3.Norway and The Allies control 2 or more victory cities (so, it could be triggered even during 9th april turn, when the Germans misfortuned to capture two cities???)
4.Germany controls all victory cities and there are only 3 or fewer Norwegian and Allied battalions left on the board
Instant only in examples 1 and 2.
3 and 4 is after German player draws last card, like below.
Marginal victory - checked after the German player draw the last card form German deck
1.Norway and The Allies control one victory city
2.Germany controls all victory cities