[Kurona]

Diend shoving his way into a Den-O movie trilogy and (through virtue of All Riders not having an exclusive Rider) having his series' "movie/dark rider" be a Den-O rider who's a cop is... it's so perfectly Decade and so perfectly Den-O that there is zero room to complain about that. It's kind of beautiful? If anything I'm ashamed of the franchise to not have Cop Den-O show up whenever Decade needs some dark nemesis pulled out of the ever-present Shocker Revival Portal to fight

In fact the only complaint I really have here is that outside of Complete, Diend's only summons are the Riotroopers! Have a bit of fun with it; lean into Den-O's comedic antics by summoning guys like Scissors and Garren, or even summon Zeronos to make every single character involved extremely confused about everything.

But ah well. Minor nitpick! This is just a fun, solid movie and the only reason I'm going on about these outside observations is that you said basically everything else I could have. Just... yeah, good Diend movie! Not what I expected from the final instalment of Den-O until Kobayashi next wrote a Rider show, but I'll happily take it!