Something clicked today, and I not only managed to place highly on both the Challenge and Time Attack mode score tables, but I then went on to smash the highest scores already there. So, that’s it then. OK, I can go back and try for higher scores, but I have “beaten” the challenges set out. Technically then, I’ve completed it.
I got 103 in the “hidden” bubble bursting game too. Shame there’s no high score table for that too.