Aqua - Part 2

For 40 Bolts, and intentional Game Over is used for optimal bolt gathering. There is a branching path with a checkpoint, each paths with a bolt. 

First Three Screens

Use Grenades and the buster as needed to pass the snails on the first screens.

For 40 Bolts, Use Astro your first time through the second screen to both raise the water level, and collect the first bolt. This makes the lower path on the next screen accessible

When following movement through the third screen, a few things to keep in mind. Snails falling through the water destroy squids they fall through. Be ready to do ball jumps up to the top (on your second pass in 40 bolts)

The second bolt is on the bottom right of screen 3.

Vertical Screen

Both vertical screens have bolts

Walk back and forth between the first row's bombs to lower the counters quickly.

Hold left on the second level to fall through the gap between the bomb and the wall.

Repeat these techniques going down (holding right against the lower bombs) to reach the bottom quickly. There is optional health here that could make damage boosts on the next screen safer.

Last Water Screen

The main ways to speed up this screen are sliding on the spike-mines. While not instant kill, they do a significant amount of damage.

If for some reason you used an astro crush on this life, collect the weapon refill - you need them all for Aqua Man