I'm happy it finally happened, after years it finally happened and the levels are quite fantastic and a new touch of things.
However, I'm not prone to it being stuck in a single mission and would actually like to see this in the Arcade after Depth 29. Making it into an endless-gauntlet type tier with endlessly increasing difficulty with a higher reward the further you go would be quite enjoyable in my book.
Even then, the core is open in missions but Arcade needs to get it opened.