Scratch

Well...Let's think here...for high score, in the nuke's coding, I'd say

if <touching color [#bbffff] //if touching the nuke
change (score) by [1] //change the score by one
end

when gf clicked
forever //always check for:
if <(score) > (highscore)> //if the score is higher than the high score
set (highscore) to (score) //set your highscore to the current score
end
end
[/scratchbolocks]
As for nukes, I think to do this efficiently, 2.0 has cloning, I think, so you'd have the bullet clone itself. Otherwise, you're just going to have to make a bunch of nukes and have a variable called CurrentNuke. After a nuke either hits the bottom or hits a submarine, have it set CurrentNuke to whatever number it is. When space is pressed, make each nuke a script like this:

When [space key v] pressed
if <(CurrentNuke) = [Number of the Nuke]
go to [ship v]
show
repeat until <touching color [#bbffff]
 change y by [-2]
end
end