This is the reason why I love this site
Excellent find and excellent guide guys, it really really helped with the Ace achievement!
A couple of tips from my experience:
- It is not very clear at step 5 of the guide, but you must do the attach-detach process 3-4 times at least to be low enough and not get hit. The last attachment must be from the controller of the player that needs the achievement.
- I found it much better bringing the ships near the right end of the screen (with the other controller), as it help hitting more enemies just when they appear on screen and also the mines do not block you as much as they do if you stayed on the left side.
- For all the boss fights, except the one on level 5 the best position is on the left as you can aim easier on their week spot and they cannot reach you where you are. The boss on level 5 fires a wicked laser shot that will get you and kill you if you stay on the left (yes I learned it the hard way...). So stay near the right end just below his weak spot and fire vertically up to get him.