There are four difficulty levels, as follows:
Easy :
These models are suitable for anyone. They are generally constructed from a small number of simple parts and don’t require any complex cutting or folding.
Medium :
They can be complex, or may include small parts. They require precision in cutting and folding.
Hard :
These models usually feature a complex design or/and include very small parts. They require precision and experienced manual dexterity.
Very hard :
These models feature a complex design and include tiny parts (no more than a few millimeters). They may require a magnifying glass and tweezers to cut out, fold and glue.