The difference between 0.1.1.0 and the current build is night and day.
Here is a blog post layout covering the significance of that specific early version and why "part2.rar" files are a gamble you don't need to take. Kerbal Space Program 2: The Ghost of Version 0.1.1.0
Version 0.1.1.0 was Intercept Games' first attempt to stop the "Kraken" from eating everyone's frame rates.
When KSP2 first hit the shelves, it was... heavy. Even high-end NASA-grade PCs were struggling to maintain 30 FPS.