There is a difference between PRINCE2, PRINCE2 foundation exam, and PRINCE2 practitioner exam.
If you mean PRINCE2 the project management methodology, then it can be a bit hard at first, since it defines some rigid standards for project management and there's a lot new things to learn.
As for the PRINCE2 foundation exam, then most of those who took it say that you can pass the exam simply by memorizing the book "Managing Successful Projects with PRINCE2 Manual". The general consensus is that this exam is fairly easy.
As for the PRINCE2 practitioner exam, most say that it's really hard to pass without the help of the extensive training course.
Both the PRINCE2 foundation and the PRINCE2 practitioner exams are multiple choice exams.