I'm not sure you can really judge the quality of a game in 30 minutes.
I'd also posit that the inability to enjoy a game that most gamers do is a problem. It means that you get less enjoyment from the products you buy than others.

Does the game play change --- other than getting more wacky abilities? Any enemy variety except splicer after splicer with the random Big Daddy thrown in?
You could posit that... although it would just sound like a bunch of trumped up rhetorical doublespeak much to the same effect of employing words like 'posit.' Suffice to say (see what I did there!) I could find some random yahoo off the street who might get a hundred hours of blissful enjoyment playing with a balloon doggy but the fact that I wouldn't probably isn't indicative of deep rooted metaphysical turmoil.

I'd say your misunderstanding the meaning of the word problem. Problem doesn't necessarily involve something major. 1+x=2 is a math problem, but it isn't all that significant. It does, like most problems, lessen your enjoyment of life, because, really, who likes to do menial math problems?
Also, I don't think you understand what doublespeak means.

At the very least, the first half of Bioshock is stunning. Admittedly it does lose a bit of steam in the second half - but to write it off after one level is kinda ridiculous.
It hasn't introduced half the mechanics, you haven't started customising your character, you haven't started modifying any weapons, you haven't encountered any of the cool enemies characters, levels or storyline.
It stays a shooter throughout, but even as a pure shooter it has enough strong points to make it worth playing.
My only problem with it was it had too much shooting, so not enough quiet time to just look around the world. But other than that it is system shock 2.