First, in Raiden 3, it seems it's possible to play with two ships (red and blue) while in single player mode. Ie the game takes only one credit, scores from both ships are added to the Player 1 score, and you still have only 3 lives in total. It's like a souped up version of Galaga's double fire mode. You need to keep the fire buttons down (I think), hold both joysticks either up or right (I think), and press Player 1 start (presumably with your nose or something
). Anyway, saw a guy playing like that and it was pretty cool, most of the time he kept his ships together ofcourse, but he'd also spread them out and aim and dodge independently, I assume he went home severely cross-eyed 
Second, in DDP, it looks like there's a bug in the stage Area 4 boss. The trick somehow seems to be, if the thing is on fire, but still lasering, stop shooting. Then dodge the laser and spread stuff for a cycle or 3 (4 ?) and only then destroy the thing. Or some shit. Result, the boss doesn't move and doesn't fire. You can just laser down the remaining 30% life or so while having a coffee. Very weird. Worked both on first and second loop...
