This tutorial will show you the two fastest ways to farm coins in Astro Bot.
Method #1
The first method is to play through the Dude Raiding stage until you reach the section where you need to use the giant slide.
This level has a lot of enemies to go along with many coins littered throughout the environment.
You can get around 250 coins for every run, which lasts around 2 minutes if you are quick.
Method #2
The second method is in the Final Encore level. This stage has gold coin boxes that you can get to relatively early. These will give you 30 coins each if you break them successfully.
You can get around 150 coins for every run, which lasts around 1 and a half minutes if you are fast.