Hi, first of all thanks for you kind words. The Requirement for a bronze star in this level is 32, which looks like a typo to me as it is just 2 lower than 34 for Silver. As you have only 26 points you get no bronze star.
So the game itself is not buggy but it definitely looks like I messed up with a way too high required value for bronze.
Thanks a lot for that find, I'll change that in the next version :-)