That certainly doesn't apply to the present game/developer. The game was finished and the old version consists of Act I and Act II, both freely available here (presumably forever). The developer remastered Act I and tried to put it on Steam as a free prologue / demo. Unfortunately Steam rejected it and told him not to reapply, so the prologue (former Act I) is only available outside Steam, still free. Act II is the main part of the game and the only one that the developer will sell on Steam. I am not aware of any plans to split the game, and extending it apparently makes little sense given how it ends. (I cannot access the game's Steam page in my country. So if I am missing any information on the Steam page, then that's why.)