The ICO castle not making much sense as a real place actually makes some in-game sense. Its magic.
But what about Portal? The parts of the game outside the test chambers were more gamey than the chambers themselves. Lots of pistons with no purpose, a severe lack of ladders or railings, deadly brown liquid flooding rooms, etc. I'm thinking of Portal 1 here since I haven't played the sequel, but was that fixed or addressed? Not to mention any place requiring "test chambers", especially one built entirely underground, is only going to have a handful of large rooms that would then be reconfigured and the subject returned to their cell between tests.
This is why its best to not overthink a lot of games. You are going to have to break from reality at some point.
The castle collapses and the entire island sinks when you kill the Queen. Clearly she was holding it together and most likely "built" it.
But what about Portal? The parts of the game outside the test chambers were more gamey than the chambers themselves. Lots of pistons with no purpose, a severe lack of ladders or railings, deadly brown liquid flooding rooms, etc. I'm thinking of Portal 1 here since I haven't played the sequel, but was that fixed or addressed? Not to mention any place requiring "test chambers", especially one built entirely underground, is only going to have a handful of large rooms that would then be reconfigured and the subject returned to their cell between tests.
This is why its best to not overthink a lot of games. You are going to have to break from reality at some point.