No messing, straight in to the Introduction, with an adventure summary for the DM and providing background to Larvik Island and what's really to be found there. Are the rumours about vast treasures left behind by Larvik the warlord and adventurer of old true? Or has someone got there first?
There are some nice touches about embedding Larvik into the local area as a figure of historical significance and renown, useful for flavour whether you are running this stand-alone or intend to embed it into an existing campaign. Maybe the characters see a statue in the town square or even hoist an ale in the Larvik Arms whilst you set them up to begin the adventure. Two different quests are provided for you to choose from based on the interests and motivations of your group, or they may have already heard rumours of treasure to be had and need no further prompting to go and investigate. As they prepare in the local township there is opportunity for some role-playing interaction to gather legends - some useful, some less so - about what they might find on the island. It's kept to a minimum unless you want to expand on it, so that eager characters can just get on with the adventure.
Next comes a description of the island as seen from an approaching boat, and information about what they'll find when they land. The location of the entrance they are supposed to find is detailed as well, which will require some thought and mapwork... actually, this reminds me of an early exercise I teach in my land navigation class! It doesn't get too cerebral, though, there's plenty of encounters with local wildlife and more to keep them on their toes, before they find any of the subterranean places provided for them to explore.
The entire adventure is a pleasant meld of an 'old-style' approach to adventure design coupled with the precise detail for each encounter that the D&D 4e mechanics provide. Several evocative player handouts are included, not just maps and notes but some of the 'you see this' style of illustrations reminiscent of early modules. Intended as the first part of a series of adventures, this will work fine as a stand-alone, or part of your own campaign (which could, of course, accommodate further adventures in the series if you see fit). It's a good example of what can be done to provide exciting low-level traditional adventures with this ruleset.