I absolutely loved it there. It felt like I was in a completely different world (I kept thinking of game of thrones). We spent the night on the island and were able to wake up early to go out to the bridge and watch the sunrise. Then explored the entire island when no one was there yet. It was a surreal experience and something I will never forget.
Touring the castle is the main activity to do on the island. Buying the audio guide is a must to learn information about each room.