You may be able to influence the die roll a little, but you should never rely on it. Your tactics will need to be updated on the fly. And beyond the ruleset, it's D&D in the sense it requires constant improvisation. Not just D&D in its looks and recreation of Baldur's Gate and the Forgotten Realms, but also in its adherence to a rigid ruleset. The first tease early last year of Baldur's Gate 3 was light on details, but after watching nearly three hours of gameplay and sitting down with the ever-passionate team at Larian, it's clear this is truly D&D: The Video Game, combined with the natural evolution of Larian's excellent RPG craft. It would be easy to assume that with the praise rightly heaped on Larian Studios' two excellent Divinity: Original Sin games, the team could just reskin what's been before in the rich coat of Dungeons & Dragons and its Forgotten Realms. It's very similar to the opening of Divinity: Original Sin 2 following your shipwreck on the beach outside Fort Joy.
There's some recruitment and chatter, a few things to learn about your impending quest, and a handful of folks to recruit. Baldur's Gate 3 begins with a group of survivors piecing themselves together after a shipwreck.