I actually agree with Jeremy.

The stage goals should encourage you to plan the work, and should if organised correctly, provide incremental functionality gains. This is a good way to work for two reasons. The first, you feel like you are making progress because you can see the improvements... sitting their coding without seeing any gains can be very disheartening and this is an all to easy situation to end up in if you don't plan. And there is the second big plus... good planning (whether you are a hobbyist or a seasoned pro) can make the difference between success and failure and if you have goals that you can mark off... its more progress that you can see, which of course helps the first reason.

It should also be remembered that the goals only account for 20% of the final score. If you have a blindingly original concept that is implemented well, looks nice and plays well, then you could still win by getting high scores on the other sections.

Overall though, I like the general concept of casual games... I also quite like the timescale. Its not so much of a commitment and so more people may compete.

Just my $0.02