Huh -- the scenes set in the past were filmed at Mt. Iwafune, which is a really nice location but is really getting overused in tokusatsu these days. I halfway expected Kengo to run into the Zenkaigers, who seem to go there every single dang week.
Hmm... I wonder if they have access to fewer locations these days due to COVID restrictions, and thus have to reuse the same ones more often. My first thought was that maybe Mt. Iwafune was fairly close to Tokyo, but it's actually a couple of hours' drive, significantly farther than a lot of other standard toku locations.
Hm, so it looks like they're doing a time loop sort of thing where it turns out the reason Kengo was picked as Trigger's host in modern times is because he was the one who redeemed Trigger in the first place 30 million years ago. Okay, whatever, but I wish he had something more to offer than the same old repetitive "I want to make people smile!!" catchphrase he's been spouting since day one.
I can't help finding it odd that the characters 30 million years ago are not only speaking Japanese, but are speaking it complete with English loan words like "Eternity Core" and "excellent." And yet Yuzare doesn't recognize the word "smile." Although the really weird part was Yuzare saying "R'lyeh means 'hope' in our language." Why wasn't she speaking her own language? I'd assumed it was some thing where they were telepathically hearing each other speak in their own languages or something, but then neither that line nor the "smile" thing would've made sense. Not that humans existing 30 million years ago makes sense either, so whatever.