7D2D is goal-driven: Every 7 days a horde comes and it’s bigger every time. So you have to build bigger a bigger & stronger fortress, you need to scavenge for gun parts, make ammo because you’re going to need a lot.
To build bigger & stronger fortress, you’re going to need iron, cement & a whole lot of wood. These require scavenging & mining. And then there is that pesky need for food & water, which you better not forget.
There is a reward system to scavenging: You get loot in the form of new clothing, new weapon parts, new books to learn new recipes, seeds to grow plants, and lots of scrap that you can shape into a variety of things that go boom.
Minecraft really didn’t have a goal other than exploring and seeing how self-sufficient you could get so you could do more exploring (*disclaimer, I haven’t played MC in 2+ years). With 7D2D, every 7 days you are measured on your ability to prepare & survive the onslaught.
As far as a quick start - you will be killing zombies within 5 minutes of starting the game. Hence the brutal learning curve.