The demo is about an hour if you take your time, more or less. After you've finished it, you unlock a mode that lets you challenge the boss again, this time with more of your moves unlocked and a new costume.
My main concerns about this game before playing this demo were about movement and especially combat. Happy to say on both counts Shift Up has done a good job. I might post a full playthrough of the demo, but it's already been done many times over on other channels. For the most part I just wanted to post something just to show some support for this game.
Currently, TheKingOfRuckus has 135 views for Stellar Blade across 4 videos. Less than an hour worth of Stellar Blade videos were uploaded to his channel, making up less than 0.92% of the total overall content on TheKingOfRuckus's YouTube channel.