Also some of the temporal clues were very good, some were 'wtf'.
I also laughed at some of the hallucination I witnessed. Like a group of people staring in a telescope pointing straight at a white wall.
Fun though, just needs to be honed in a little.
It would help to have markers on the timeline for the different ages, at least for the first round! e.g. Bronze age.
You already sort of do, being a Gregorian timeline and marking 0 AD as Christ's birth. That's a dead giveaway when you see crosses. So I think it would be fair and useful to give a range of eras as markers on the timeline.
The map could also be continental, and the locations more precise than the country.
The map could be more exciting, and change based on the timeline selection! It's currently showing the "current" map and not the map of the era; which in some respect is relevant.
Finally, the scoring could be more explanatory, you got 5,000 / 10,000 for the following reason / calculation method. Maybe a graph of points per time correction and location. It could also be more comprehensive scoring, with a slight multiplier for streaks, a badge for being good at temporal location vs. geolocation etc.
Scoring could animate up, to gamify the experience, create a sort of level end screen that builds up excitement. The map could animate and so could the timeline in this end phase.
I like the idea, there is a lot you could do to push this further.