Well written and sets the scene well.  I'm looking forward to seeing what happens next.

It's not particularly difficult to find the inspiration for it. It screams Indy all the time. That has me wondering: Will Mum's diary somehow end up with an autograph of, shall we say, an infamous person? :)

It's a shame you didn't manage to include voice-over and audio in the game, but it works just as well. This snippet is an intriguing introduction to an adventure/treasure hunt. There are a few tropes here, but that's what I expected when I started reading It's part of the fun. I like that you tied Ben into the story at least once. It makes him more interesting than just standing there (and basically being a clever hint system/fluff). One thing I'd like to have toned down a bit is Jane's knowledge. One of the interesting things about younger protagonists is that they don't know everything and have to figure things out first. A know-it-all can get on your nerves pretty quickly. This is of course my very personal opinion and may differ greatly from others.

There are a few typos and missing/incorrect words here and there, but that's not a big deal and can be easily fixed without the tread of an imminent deadline. :)

Oh, and thank you so much for the ability to go back a page (or more) at any moment. I really appreciate that.

Hopefully you will finalise the project after the jam. It will be interesting to see where this is going. looking forward to see more of Jane and Ben.