Like the venerable Lantern before it, this is a lot like Magnifying Glass for Survivors. Instead of an emergency damage source (or being played fast in the case of MG), the bonus effect on this one is the ability to reroll a failed test once per turn. Not a bad kicker at all if you're just looking to grind out one clue per action. I think I'd usually prefer Nautical Charts for the innate clue compression, but if you're playing a character that's not good at drawing cards, Old Compass be what you want. Synergy with Stella Clark who wants to fail tests anyway; if you fail this test, you get a free reroll AND your bonus action, nice!

A strong enabler for Darrell's Kodak is Dr. William T. Maleson (2). This allows you to manipulate what encounter cards are drawn (for yourself or an ally) to get a treachery that generates evidence, in addition to dropping a clue so that you can gather evidence on your location even if it had zero clues on it before the mythos phase. Another thing to keep in mind is that you don't actually need to be at the locations where the evidence is, just discover clues at them. Shed a Light will let you snap a pic of the enemy your guardian is currently fighting four locations away.

You don't want to rely solely on the Kodak though, as you at best get one evidence per round. Luckily Empirical Hypothesis has got you covered. All three cards are part of the same expansion as Darrell Simmons and are great cards on their own for him.

"For every 2 damage" usually means a multiple of so (2,4,6,...) then the "(rounded up)" is obsolete isn't it? unless they mean "gains ? equal to your damage divided by 2 (rounded up)" but the why don't say so?

How do you advance from Out of This World? It doesn't say anything like "investigators can spend clues together to advance".

Is there some other way to do it or was it left out? Couldn't find any errata mentioning it.

TLDR; This is Clairvoyance & Sixth Sense having a special child together.

Upside: For with low you could keep using your for getting clues without spending any charge if you runs out of them or only need to pick 1 last clue at the spot. Plus, the spend charge for 2 clues per action is decided after you finished your skill test, so you wouldn't lose any charge privilege if you fail. (yeah... still a pain but the chance is not that high... right?)

Downside: Though the chances of discard from is obvious, the unseen downside of this card somehow lies on its upgrading path. Unlike other most spell which has middle stage before fully upgraded (ie. Clairvoyance(0) > Clairvoyance(3) > Clairvoyance(5)), you either go LV 0 or LV 5 so you couldn't take much advantage from Arcane Research, even worse when at fully upgraded version you still get 2 clues maximum per action unlike other high level options (which... might arguably be better?) But since we are talking about LV 0 version here, and at LV 0 deck we don't have much recharge options at the beginning, I would say it's still worth taking it over Rite.

Final Thought: Everytime I used someone's Mystic build for 4P runs I always swap their investigation spell with Second Sight(0). Aside from chances of losing it before recharging it back, this spell is just straight up better than Rite of Seeking. And if you are tired of smelling the same incenses from every Mystic build, you could absolutely pick this over Clairvoyance.