I booted up Slay The Spire with Mod the Spire, BaseMod and STSLib installed, along with three other mods. Right from the Mega Crit logo at the very start, the game was freezing for about 5-7 seconds at a time, running for about half a second, then freezing again. This repeated relentlessly. Even alt-F4 didn't do anything until the next half-second window.

I disabled the other three mods, and launched with just the basic three listed above. Same issue. I disabled all mods and launched the game with just Mod the Spire. Same issue. I tried launching the game without mods, and it ran as smooth as butter. There's clearly something wrong with Mod the Spire itself.

Any ideas?