Twofold Tower

Here is an excerpt from Twofold Tower's Steam description:

Looming above the apocalyptic wasteland is Twofold Tower – a mysterious, sprawling monolith of a thousand rooms. Enter at your own risk, for inside monsters lurk in the shadows; laws of nature are treated as mere suggestions; and forbidden knowledge is everywhere to be found…

Features:

• Mad Science: Experiment with 100+ distinct game mechanics, including parallel dimensions, time manipulation, modular game rules, monster manoeuvring, and much more…
• Tons of Content: 1000+ handcrafted puzzles across 50+ hours of playtime.
• Quality Over Quantity: There is no "filler" in Twofold Tower, with every puzzle exploring a unique idea.
• Sprawling Exploration: Navigate nonlinear, themed levels, which are connected by hub levels – hiding plenty of secrets, and making it possible to return to a puzzle later if you get stuck.
• Deliberate Problem-Solving: Fully grid- and turn-based gameplay, with a particular focus on outside-the-box thinking, inspired by titles such as Baba Is You, DROD, and Braid.
• Quality of Life: Care has been put into making Twofold Tower comfortable to play, with snappy animations, undo, controller support, and QoL features such as marking tiles on the grid.

While never obscure or difficult just for the sake of it, the narrative does respect your intelligence, and brings together ideas from many different areas, including science, philosophy, spirituality, and religion.