StingingVelvet: That's what games are though, right? In FEAR you shoot dudes through a level, then move to another level and do the same thing. And FEAR is one of the best shooters ever made.
You could describe any game that way.
In Mario you fireball your way through a level, then you move on to another level and do the same thing.
In Zelda you hack your way through a dungeon, and then you move on to another dungeon and do the same thing.
In Ghost Recon you plan how to advance and then deploy your units to put your plan into motion, then you move on to another level and do the same thing.
In Monkey Island, you click on things to make stuff happen in order to get to new places so you can click on new things.
You write as though I dislike games that focus on gameplay mechanics, (previously referred to as "core gameplay",) which I don't. Each of the games I listed are games that basically have you do the same thing over and over everywhere you go, and they also happen to be some of the most entertaining games I've played.
However, if I had to play the same level in Mario again and again to get to the end, I would grow tired. If I had to get through the same dungeon again and again in Zelda, I wouldn't bother. If I had to play the same map again and again in Ghost Recon, I would have quit. If I had to work my way through the same room over and over again in the Monkey Island games, I wouldn't bother.
I don't want a different type of gameplay mechanics for every room I visit in a game, but I do want different rooms in which to play around with the one set of gameplay mechanics that the game comes with. This is why I can play Grim Fandango and Full Throttle and Flight of the Amazon Queen and the Blackwell series after playing Monkey Island and still enjoy each and every one of them. Their gameplay mechanics are identical, but the worlds are different.
And that's where AC1 was an enormous disappointment.