Lots of things to explore
The "what's-what" of Guam is all told in this one-block area of San Vitores Rd. (I'd also like to say the previous comment is about only ONE part of Pleasure Island). In the short walk from The DFS (Duty Free Shopping)Galleria, to the SandCastle, there are so many things to do, you could spend the whole day in this one little area, and not get bored.
If you're lucky enough to be there on certain days of the year, the people of the island hold many "block parties" on Pleasure Island, including-but not limited to- "Hot Import Nights": A yearly gathering, featuring the best of the best custom cars. The yearly "Pleasure Island Block Party": Featuring the sights, sounds, tastes, and experiences to be had on pleasure Island.
I'd say Pleasure Island is one of the Guam's "Must See" 's