Okay, so, this whole idea of "Changelings join forces with the Borg to assimilate all of Starfleet" is... a bit over-the-top. Like, it's the kind of premise bad fanfics are built around.
But, this was a very well-executed version of that over-the-top premise.
It was really wonderful to see Elizabeth Dennehy and Alice Krige return.
Shaw's death was excellently-executed. His final words were an appropriate redemption.
The re-creation of the Enterprise-D was great.
The credits say they used Majel Barrett again as the computer voice!
Final note: This whole thing were the text of the story is literally, "All the young people get brainwashed by evil foreigners and only the Boomers can save us" is... not the kind of idea I would want to see people adopt in real life.