Lucky's Puzzle Carnival ($13, free demo) is a game which desperately wants to be liked, and I wanted to like it...but with PopCap raising the bar on casual games, Lucky's is average at best.
The Puzzle Carnival features three puzzles: The classic memory match game, a game in which you add colors to balls to form rows which then pop, and a game in which you juggle rows and columns of symbols to restore order. The games are fun enough, but they are fairly straightforward, without the usual modern contrivances of power-ups, unlocked animations, or a storyline linking them together. As you complete games in a series, you slowly reveal a circus poster as a reward. The "world tour" consists of posters of various cities. You also struggle to beat your best time, and the "par" for each puzzle, which may be based on time or the number of moves you need to make to solve it.
Lucky's Puzzle Carnival is extremely minimalistic in terms of sound and animation. There's a spirited background melody, and the occasional "Good job" speech, and that's about it. Animation is very limited. The interface, while clear, has just a hint of sluggishness to it, that small delay in responsiveness which is just enough to be noticed. (Lucky's seems to be written in Java, which explains this.)
The trial version has a limited number of levels; the full version unlocks them all. Lucky's Puzzle Carnival is a good game for younger children who may be confused and overwhelmed by the plethora of sights and sounds of other puzzle games; it might also be good for those who just want to solve puzzles and not bother with clingy unicorns.