They are. JSK releases free games on his site to drum up interest on his paid games as well.
He's probably playing Kantai Collection like every other otaku in japan, and is trying to capitalize on that desire to fuck those shipgirls.
All of the kantai collection free games are straightforward missionary position games with unique dialogue that fall in line with the girl's personalities.
You can find all the games in
@Delexicus 's signature. There's a mega link that has all the currently translated versions of all the games.
If you like them though, it'd be really good if you could buy them. JSK's output is much higher now than it used to be, and I'm guessing it's because he switched to game-making full time most likely. I think if his financials get worse enough he'll definitely disappear for good.