I tried my best to really enjoy this castle, I achieved middling success. After already visiting Frederiksborg and Rosenborg, my efforts to visit even more castles were not filled with much excitement. Nevertheless, I started the day walking to Copenhagen Central station and getting on the train to Hillerød. After the exquisite Fredericksborg, we took the train to Helsingør.
We spent about 2.5 hours at Kronborg. The views from the tower were stunning and one of the prime locations to understand OUV as the layout and elaborate fortifications were all on display. The next primary site of interest for me was the sub levels of the castle, in which food/drink was stored, protection during a siege, and some of the oldest components of the castle. You can enrich your visit to this portion of the castle by waiting for the guided tour.
Lastly, I should mention the Hamlet connection. Actors are usually on-site. There are scenes that are (somewhat) spontaneously orchestrated throughout the castle interior and exterior at different times. We viewed one scene by the fountain, and I would say it was enjoyable enough and added a bit of fun to the visit.
Most of the interior of the castle is not particularly interesting, and little is on display. Once again, the castle is covered with the Copenhagen Card, which is convenient. Kronborg is very much worth visiting, but it suffers in comparison with other Danish castles both in North Zealand and Copenhagen.