According to the invite, the invites are for the alpha stress test beginning Friday morning and winding down Monday.
“This is a technical test and an opportunity to explore our first Frontier, the Goblin Forest. Defeat bosses, discover powerful gear, and wield your first Relic Weapon this weekend.”
It does seem clear that the NDA remains in place, so don’t expect any Twitch streams where you can take a peek. A presumably more open beta, and the launch itself, is still expected in 2019.
🗝️Alpha keys going out!🗝️
Check your inbox over the next several hours for an email with your key. If you haven't received one yet, don't worry; more will be sent this week!
— Play Torchlight (@PlayTorchlight) November 13, 2018