itch.io

no clue about the size thing, a few dev logs back there was an unofficial guide announced, its pretty up to date but honestly not sure how good it still is. it'll get you through at least the early game though. 

here's the link to it

https://docs.google.com/document/d/17kLfYcixr3ZiD8_X-WmRs1mNaYoTF-cG7Ivy2HpBmjw

Here is another guide for the game that is maybe a little more up to date.  It covers up to version 4.2.3

The current walkthrough is accurate up to 4.2.3, and we're updating it soon - there's a link to it in the main menu of the game.

We use compression on public builds, to make sure they stay under Itch's upload limit - it's largely invisible, but does a lot to reduce our filesize.