Just hold down or click the mouse and if your device can (probably barely, if anything) handle a custom block with an F1 engine rammed inside, the screen will turn from red to green, and hopefully it won't crash! Lovely jubbly.
I created this to test NateXS's Scratch Everywhere on my New 3DS (it froze the system in the latest nightly build, thus requiring a restart), all in the hopes of getting my Gummibär album intro recreation's scaling fixed (see https://scratch.mit.edu/projects/1216584521). Still, if there's some other Scratch reimplementation you wanna try, be not just my guest, but its developers too. There's also another test I created for the resolution detection that happens inside: https://scratch.mit.edu/projects/1230826263.