Multiplayer isn't even required to beat the story, it's still entirely possible to do so without. - And much easier to do so than it was in ME3 Open world RPGs have existed before Destiny was even in concept. The new mako looks like it'll actually work. We can jump now. You're not restricted to one class (Infiltrator, Soldier, Adept, etc). Still though, don't preorder. Pre-orders are cancerous and all the bonuses you can still get weeks after the release.