Personally I didn't mind the ep3 intro or the Battleships music. I liked that Martian Lovesong (the 'devres theme') wasn't used until the final scene level, otherwise it'd feel overdone - for me, at least. One thing I'd change about the ep3 intro, though, is removing the autoscrolling stars from layer 1 that weren't seen in the ep2 finale. That always bugged me (I complain about the most irrelevant crap)

Making the ep5 intro stand out from ep3's would be beneficial, and something as simple as changing the tileset (like to BattleshipsBL) might work.