I have some issues with the economic system of the campaign. Twice I have played as Japan vs the World and twice now I have more or less to stop the campaign around 1917-18 (start date 1900) because I am bankrupt. I do not loose any transport ships, I've captured many regions close to Japan and I have far less ships than the major combatants. The problem is that while they can run their economy down the drain, use too much money to built enormous fleets and have admiral after admiral scaked and still go on, I cannot do the same.
Also, I have noted that the other nations still build up enormous monetary reserves, even if they loose war after war, loose regions and build humongous fleets. In other words, it seems to me that it is impossible to beat the enemy economically.
Furthermore, after I finally ran out of money for the first time in my last campaign, around May 1918, I did not get any replenishment of money. Is that a bug or intentional?
I've won all my wars, I have not overbuilt the navy and I have decomissioned older ships and designs, yet this economic breakdown seems to happen every time after a while now. For me it breaks the campaign forcing me to start over. It could be a serious obstacle to play the game.
If I may make a suggestion to one solution to the problem of the enemies having admiral after admiral sacked, it should be that if an admiral is sacked due to using too much money, there should be a forced reduction in their fleet.
I hope the development team could have a look at these issues as it is seriously impeding my abillity to play the campaign to the end now.
One last thing is that despite having based my submarines very cloose to enemy ports I have yet to see an option to use them in fight. The window with options to to play out a battle or run away never appears. It seems I cannot get them to do anything.