In addition to the challenging boss battles, Another Crab's Treasure also features a number of tricky puzzles that are difficult to solve. Most of these stem from the Flotsam Vale level and the electric magnets.
How to solve the magnet puzzle in Flotsam Vale | Another Crab's Treasure
You encounter the first magnetic puzzle shortly after you open the electric gate as part of the main story, and no matter what you try to do, it feels like there’s no way to get through. I was baffled when I first encountered it, and it took some button mashing to figure out the solution.
When you finally get it, you might feel a little bewildered, considering how simple the solution is. But if you’re still having trouble, don’t be discouraged. This is exactly what you need to do.
To solve the magnet puzzle in Another Crab's Treasure, go to the machine next to the red magnet and interact with it. It will spit out a Spring shell that you can attach to Kril.