Okay, so here's the deal - you can access the beta for the Season 5 Void content at 11PM EST tonight, through Monday April 18th at 08:00 EST. You'll accomplish this by right-clicking on it in in your Steam library, selecting 'properties' and then the 'beta' tab, like so:
Then, select The Void (beta), and you're good to go.
It's not available yet. Yes, I checked. What is The Void, you ask?
"It is an extension to the existing season-based story but with a twist—instead of continuing with the same story based missions, The Void is an endless mode in the chaotic depths of space where you can enjoy the core moment-to-moment gameplay at the heart of GALAK-Z. Every run in The Void ends only by perishing. There are no save points. There is no mercy. However, your score will be posted each time to online leaderboards so that you can compete against other players’ high scores."
Once all is said and done, Galak-Z will include a Daily Challenge Mode, which permits players to get decked out in a universally-shared set loadout - same as every other player trying the daily challenge - to take a crack at being the best in the world.
Void Run, also a new mode, permits players to attempt a potentially-infinite session of Galak-Z that will collect your high scores for leaderboards.
Now if, like me, you have a shit computer and you really just want this content to land on PS4? Never fear! "The Void will be available for PS4 & Steam players upon launch in a matter of weeks" and "more story and Void details will be revealed in the coming weeks."
(Studio head) Jake Kazdal promises "more surprises" are comin' soon too...
[update]GALAK-Z faithful! Take a sneak peek at our Season 5 Beta this weekend, more surprises still to come but details at https://t.co/3GuuUjmt1z— Jake Kazdal (@Jkooza) April 14, 2016
10:01 PM central time: