It's a little difficult to recommend a game like this with the current state of affairs regarding the now defunct Nintendo E-shop, but if you're keen to use [legal methods of acquisition] Boxboy! is a cute little time waster. I got the game before the closure of the 3DS E-shop and have been playing it on-and-off from time to time, typically on my bed or during a commute. I wouldn't entirely recommend binging through it, as it's certainly made with bite-sized sessions in mind, but I should say that I kind of binged through pretty large chunks of the game.
The game is an aesthetically pleasing albeit visually minimalist puzzler with minimal platforming. Being mostly decidedly paced in a means to not need a great dexterity, with the exception of the final level set and the post-game bonus levels. The game doesn't use the dual screens in any other means besides spacing out the content, which does further it's more minimalist visuals but doesn't particularly contribute to gameplay, with no usage of the touchscreen. If you were to emulate the game via [legal means] I'd say the second screen needn't be given too much room on its own.
Boxboy! is a recommendation for anyone looking for an on the go brain teaser that's easy on the eyes, less of a recommendation if you're just going to play it on your home system, but I mean getting it now would really only be through emulation so there isn't much harm with the lack of cost. If you have a 3DS with this sitting on it and haven't played it, it's pretty fun, give it a shot.