I did actually. I played for a good 20 minutes the first time with the two button relative controls. On first startup, the buttons appear for a short while then disappear and stay gone through any deaths / further retries until the game is quit or the control scheme is changed. Then the new control scheme buttons last again for a couple of seconds. When the snake gets a good bit longer or the wall sections happen and the button pressing starts to get a bit frantic, it can be easy to miss a press on the buttons when they are invisible. It appears to be a bug because at the point of death, the buttons briefly appear before the score screen. Just tried with the 4-Directional buttons now. The buttons remain visible on the screen during all play apart from during the walled sections, but successfully reappear when all the black cubes are eaten. On death, the buttons disappear at the point where the invisible 2 button ones briefly reappear. I'm guessing for the invisibility of both 2 button controls after a couple of seconds, maybe a show/hide toggle is misfiring, or if the invisible effect is intended for the larger buttons in those two control schemes, it would be nice to at least have the option to leave buttons visible at all times.