It doesn't have a name yet, but it's described on Gilbert's Terrible Toybox website as "classic Zelda meets Diablo meets Thimbleweed Park."
Gilbert's been posting about his new game on Mastodon (via Time Extension) since early 2024, but it's gone largely unnoticed until just recently. In February, he shared an image of a whiteboard rough-out of the opening area and quests, and a little bit of stats work; from there, he's posted a few more in-progress images, along with some brief thoughts about his process.
When the creator of Monkey Island tells you Fuck You, you definitely messed out something in your life. Shame on you Elon Musk for disappointing Ron Glibert.