Some of them are really close to each other. Most are just picked up at some random location. It actually goes by pretty quickly if you use a guide. Also interrogating Riddler guys to expose them all in the map makes it even easier. I just cleared out one island a night and that was the right amount of time.
I still believe for most people, the trophies are easier to pass up this time around because the game world is so big, so by the time most finish the game, they'll have proportionately more left over than they did in previous titles. There's also the fact that there's only one Riddler hostage who's a vigilante as opposed to just medics — it may not seem as pressing compared to the other stuff going on in this game.
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I miss being able to use all of the d-pad to select gadgets.
I think I would've preferred to have the mission wheel and especially the AR challenge wheel in the pause menu. Then have detective mode on L1/LB, Batmobile summon on left stick-click, midair line-launcher on right click and then gadget select like it was before, but holding rather than tapping in any direction brings up the wheel for the gadgets that aren't in the eight main directions, maybe with a time dilation effect. I think being able to hotkey some items and leave four for the wheel would be better.
It's not a big deal though. I just got real used to that method.
Just set a waypoint on the map.
Riddler stuff is overdone in Arkham Knight, but it's better implemented than it was in Arkham City. Some puzzles on that game were miserably put together.
The waypoints for the riddles (not trophies) only tell you a general area, and at least one tells you it's on the surface, but it's actually underground (Calendar Man riddle). You also can't mark waypoints for trophies in interiors that have their own maps, iirc. That's what made a few of those frustrating.
Which puzzles in City were poorly made? There weren't any that I remember being ambiguous or flawed compared to some in AK (like the one on the outside of the blimp).