Wow, thanks for solid feedback! Congrats on discovering the two-finger exploit. Not the worst exploit currently, but when you noticed it, others will likely notice it too.
Any imbalance in the unlocks? To me, the topscore based unlocks (5 secs, 10 secs, 15 secs) unlocks the fastest, but I played the game before, so I'm not entirely sure. I consider changing it so that the user has to do it 3 times to unlock. I'm also a bit afraid the hunt for unlocks overshadows what should be the natural goal, that is, beating your previous topscore.
(BTW you can unlock everything by typing 7913, treating the icons as a numeric keyboard)
Did you have any specific SFX in mind? It's kinda intentional that the whole aesthetic is low key and spartan, but maybe I took it too far. I consider giving th player some sort of particle trail. The lack of music is also kinda intentional, but also I don't think the music of a cellphone is ever gonna sound good, unless the user has a pair of headphones. And I have no skills at music creation, so ...
Regarding the lack of an [x] in the upper-right corner ... it wouldn't take much to implement it, obviously, but there's a whole sing-and-dance about how wrong it is to close down programs in Android. Implementing a close button is very, VERY controversial. I might do it, but, gonna research this further. But on a personal, gut-feel level, I very much like to control what's in memory and not, thankyouverymuch. So my tender soul is positive towards the [x]