Hmm, unfortunately that doesn't quite answer my question xD See, the thing is that Infamous is a 25+ gb download, but the PS4 usually lets you start playing games after just a small part of that is done. In Infamous' case, that's just 5gb - as soon as that finishes, I can boot up the game and start playing.
The confusion I have though, is that once I started downloading Infamous, all that showed up was a single 5 gb file. Now, just like you, I'm used to the PS3 way of doing things - download and then install. I know that the install step is unnecessary on the PS4, but I'm still kind of puzzled about how the next 20 gbs get downloaded - does the ps4 automatically start downloading it without prompting, or do i have to first boot up the game and it'll download in the background?
Obviously, the logical thing would be for it to continue downloading without any contact on my end, and that's what I initially thought was the case. But after seeing that 5gb file, and reading some other comments online (nothing that explicitly says I have to launch the game, but vague enough to have me doubting), I was just kind of curious to see if anyone else had an idea... again, this is mostly me a bit bored at work waiting till I get the chance to go home and find out myself XD
EDIT - Thanks for the reply though! And yeah, I love the inFamous series, and this one's looking like it may be the best one yet!