a> Great stuff with getting a solid looking game on the store, plays very smoothly, shooting works well
b> First text I saw was a typo - I hate that sort of thing, but easy to fix. (“Tap to shot monster” => should be “shoot”).
c> As you said, quitting out very slow.
d> Only real major thing that annoyed me is that when you popup a message, you don’t pause the game underneath. Need to do that - I levelled up, and wanted to see what was going on, but I could see monsters still walking across my screen underneath! Same with the shop etc - you need to pause the game to encourage people to spend, not panic back to the game.
Overall - very tidy little game, well done.