Specialty Building Upgrade Challenges

In order to buy the last upgrade of a Specialty Building, you must complete a challenge involving the tower that the Specialty Building improves. Here is a list of the challenges:

Dart Training Facillity
Complete Monkey Lane easy with 2/2 Dart Monkeys and Exploding Pineapples.

Tack Research Centre
Complete Park Path easy with up to 8 Tack Towers. 1 of them has to be a Rong of Fire and 1 of them has to be a Blade Maelstrom by the last round.

Boomerang Dojo
Complete Park Path medium with a maximum of 8 boomerang throwers. You must have 4 Glaive Lords and 4 Turbo Charges by the end.

Gonna add some more. If you have better ideas for challenges, give me some suggestions in the comments.