There are a pair of Anthem demos coming prior to its February release, one for preorders and Origin Access subscribers running January 25-27, and another for everyone else on February 1-3. They'll give the unconvinced an opportunity to see what it's all about before they commit themselves to a preorder, and in the case of the preorder demo, I suppose, will (hopefully) make the already-committed feel good about the choice.
The demo won't be exactly the same as what players will experience with the full game, however, as executive producer Mark Darrah explained on Twitter.
So how’s the Anthem demo different from the game?- we start you in the middle- no tutorials- no pilot picker- balance is super different- economy is completely different- 6 weeks less bug fixes...January 19, 2019
In follow-up tweets, Darrah said that the balance between missions, stronghold, and freeplay "will be off a bit" because there's only one story arc, and the PC controls will be "slightly less nuanced" than they will be in the full release. (I thought the mouse and keyboard controls were pretty decent in the alpha, but the flight model was a little too twitchy for my liking.)
Some names will also be changed in the full version of the game, and the demo "is easier in general," presumably to ensure that players can sample the sights and sounds without getting Mozû'ed every time they step outside.
Anthem is set for a full release on February 22. Origin Access Premier subscribers one week earlier.