Yes, I know they've reduced the number of challenges to help with "the difficulty of taking part in a challenge every week"
My suggestion is to address this difficulty by implementing more challenges and overlapping them throughout the week. A new Challenge should start every day, Tuesday-Saturday, and last for the next 5 days. Any day of the week you have the time to play Planet Zoo, you'll have one of five or six challenges to work on.
Did you miss the Greater Flamingo challenge? That's OK because it will come back around in a few weeks. Already done with the Flamigoes? That's OK too, because there are 4 others to choose from.
My suggestion is to address this difficulty by implementing more challenges and overlapping them throughout the week. A new Challenge should start every day, Tuesday-Saturday, and last for the next 5 days. Any day of the week you have the time to play Planet Zoo, you'll have one of five or six challenges to work on.
Did you miss the Greater Flamingo challenge? That's OK because it will come back around in a few weeks. Already done with the Flamigoes? That's OK too, because there are 4 others to choose from.