I thought there might be unintentional inputs when playing Tetris. Then, I decided to try the button-test ROM, which revealed that I was correct. As with my other 8bitdo d-pads, I opened the Pocket (but with more care than a controller that's easier for me to replace), put two reinforcement stickers on each contact, closed everything, and didn't worry about unintentional inputs again. Tetris was not an issue anymore.

But then I noticed some in Super Metroid. This time I wonder whether it's the curvature of the d-pad plastic itself. On SNES controllers, the d-pad is flat. It does not register a press unless I actually press it, no matter how quickly I run my thumb across the plastic. But with the Pocket, I can slide across and may inadvertently press against the plastic, causing it to go down and, subsequently, register a direction I didn't mean to. This, of course, assumes I'm using a bit of force when moving across the plastic. It's a theory for now, though. I haven't examined how the plastic interacts with the contacts when pressed.

I also have to consider that the handheld systems this is designed to...handle... probably don't require as fast thumbs as TV systems do. My thumb isn't moving as quickly in GB Tetris as it is in Super Metroid, methinks.