[Sitting Duck] Achievement - Detailed info

"Destroy 16 cannon turrets of the battleship in Scene 4."

It's a bit of a confusing achievement given that what it actually means is that you need to end up with a "16 Hits" combo by shooting 16 cannon turrets in a single session in the first battlship-related bonus zone; or at least, it's a lot easier to do so in that one bonus zone.

Preparation

Before you even start, you'll want to turn on Hitbox Display in the options menu so you can actually see where to put the crosshair to. The achievement still counts when going to Scene Select.

First section

For the first section, there will only be 10 cannon turrets for you to shoot at, so the goal is "10 hits" for this first part.

Second section

The second section begins when the above screen starts slowly scrolling to the left as new hitboxes appear by then. The remaining 6 cannon turrets can be shot during this time, but they must be destroyed before new enemies appear or else it doesn't count for the achievement, as that marks the end of that particular bonus zone. If you don't end up with "16 hits" by the end, then you'll have to start over.

Concluding comments

The second section might give you a hard time due to how relatively slow your crosshair goes and how fast the hitboxes go off screen, thus removing "lock-ons".

I don't know if it makes much of a difference, but I'd probably use the Overdrive or Bonus Fighter when trying this.