If you only see the title, it's a feature that has been suggested too many times (almost as many as zapping DE).

However, you might still feel boredom if you three-star all those newly added goblin levels.
On the other hand, buying shields also makes the game boring.


The suggestion is that new goblin levels are presented when you buy shields with gems, and disappear
if this shield runs out or you discard it by attacking.

More levels are presented if you buy longer shields.
Note that free shields gained by being attacked don't gain new goblin levels.

These levels are randomly generated, therefore you can receive new challenges each time.