Yes on the hardware back button (at least its hardware on this phone). But yes the not-the-button-you-drew-in-software back button.
Also, I had some free time so got round to getting you the log:
This is straight from running adb in the command prompt and I had to sift through a lot of stuff since I didn’t know what your apps package name was. So I might have missed something but I don’t think I did.
As for unbeatable levels, I’m going to admit that I haven’t been playing it as much as I would like (odd absence of train/long car journeys). There have been a few levels I’ve had to skip but I’m sure it was due to me not concentrating hard enough. (Not that it isn’t captivating, it was just late)