You're forgetting the fact that it's a game - and a great one at that.
The physics-based puzzles are simply ingenious and the somewhat linearity of the game is a good thing, as it provides for great pacing.
The story is great and while not a lot of answers were given, you could have derived a lot of them throughout the game. The game also features one of the best level designs I've ever seen.
As far as the striders go, whenever you come across a big or infinite supply of ammo for your rocket launcher, that's when you're supposed to kill them. I don't see how one could do it any other way seeing as you can only carry 3 of them, which isn't enough to put them down.







