coan.net: As stated, with diagonal boats, you can have boats intersecting each other. (Say one boat on a1-b2-c3, the other on b3-c2). Is that intended?
ColonelCrockett: There's a bigger advantage of going first in dark battleboats than in battleboats, because there are more shots in dark battleboats than in battleboats. The more shots you can make per turn, the bigger the advantage the first player has. (Taken into extreme: with 100 shots/turn, the second player would never win).
coan.net: To rule out any advantage of one colour, you have to make the moves simultaneously, just like in Logic. (In the implementation, the moves aren't simultaneously, but from a game aspect they are). In Battleboats Plus, the number of shots one has in move N is the number of boats one has in move N - 1.
IMO, also Dice Poker and Triple Dice Poker could benefit from having simultaneous moves, as those games give a slight edge to the player going second. But not as big as Battleboats and its variations give to the player going first.