With regards to time limits, I agree with Brian in that whether or not something is or isn't a ticking clock doesn't mean it's not still a time restriction, and I'd rather the game communicate that information in a reasonably transparent manner, whether or not a literal ticking clock need be invoked in order to do that.
Let me ask everyone this, when you're in a situation where your health is constantly dropping, or you're being chased by a helicopter, or the moon is about to smash into the Earth, or whatever, are you ever actually fooled into thinking it isn't just a time limit presented slightly differently? Why is a ticking clock in itself such a lazy contrivance when constantly dropping health or a collapsing building is functionally the same thing? In either case, the "urgency" comes from needing to complete your objective as quickly as possible, with repercussions for taking too long, ultimately leading to a fail state once a certain threshold has been passed.
In other words, you have a limited amount of time... hence, a time limit. So long as the game accurately communicates the information to you, what difference does it really make whether it does so in an obvious fashion or some contrived in-game-explanation kind of way?