E1 is going F2P, as will the "Butterflies" package, again. Keeping 2 and 3 paid DLC.
The reason is that I'm an idiot who should've done it from the start, and also that I want money.
More seriously, a lot of the feedback from people who jumped straight into E3 was that the movement mechanics were hard to figure out and poorly explained; E1 was where the tutorial was, was paywalled, and was honestly not good enough to warrant the paywall.
So I'm putting in a request to Valve to switch to free, effective whatever time I get from them.