*taken from my LB review*

Takes a good 43 minutes out of this 70ish minute film to justify itself, with such empty, indifferent plotting, but when the reveal happens, it's a pretty emotionally heavy one that starts to bring things into focus and elucidate the parallels between Ko & Teddy and Miku & her grandma.

It's a well-meaning sentiment of fighting to preserve those you cherish and not be complacent to some supposed rules/fate, though there's a lot of hanging details that don't make it as effective as it should be.

For Miku, her motives are rooted in the grief and regret of her future self where her grandma passes away and uses time travel to be able to find an excuse to enjoy the company of her grandma after not making time for her before, but it doesn't seem like the present Miku actually realizes her mistake and grows and instead it's future Miku who got to make the mistake and then go back and use her time again as a second chance while exploiting an Imagin's powers in the process to do so, feels like a morbid "have your cake (spend time with her bf) and eat it too (experiencing her birthday multiple times with different decisions)". It's not like real people have that luxury of being able to explore every option and just undo their regret, seems insincere that she's just able to *fix* it while present Miku was probably able to run off with her boyfriend too for her birthday (?)

For Ko, it's more complicated.
1): He's a character who we've only kind of learned about as a peripheral character across like, 3 movies, so he and Teddy still feel too vague to really get invested in as characters.
2): Kotaro seems to be the one taking Teddy for granted while just casually taking in all of Teddy's assistance like he's just some kind of butler for him, yet Ko takes less of the risk with regards to his contract with Teddy. Sure, he goes out to fight the villain Imagin since Ryotaro is incapacitated so he runs that risk, but the Imagin hardly seems that threatening, and maybe the other good Imagins there could've all pitched in to defeat the baddie (Sieg's inclusion here is pointless and is played off like a lame joke). Teddy meanwhile, runs the risk of permanently being erased by breaking his new contract with the Owner, so him going out of his way to assist Ko has more stakes than Ko trying to take Teddy back by force, even though Ko & Miku taking things for granted is the point.
3): The Owner's contract term just to teach Ko a lesson still feels so arbitrary, while Teddy's apparent revival might in fact only have happened because of his strong connection for Ko, but putting Teddy's existence maybe at risk for some corny lesson under the contract pretense of...helping him buy big spoons (?) is just so odd, this movie has some really bizarre stakes.

Kobayashi ends her Den-O run with one of its strangest, weaker efforts, but maybe just a notch above Onigashima Warship. Disappointing to see all this mostly whatever extra material for Den-O that don't feel especially necessary, even as a fan of the core series.