Idris Elba as Knuckles is the most galaxy-brain casting idea ever conceived of.
Dr. Robotnik (Jim Carrey) has been banished to the Mushroom Planet, but he finds a way back to Earth with the help of Knuckles the Echidna (voice of Idris Elba) who is seeking the Master Emerald, a source of unlimited power. With his adoptive family (James Marsden, Tika Sumpter) in jeopardy, Sonic (voice of Ben Schwartz) has to fight both Robotnik and Knuckles, this time with the help of Tails (voice of Colleen O'Shaugnessy)...
At no point in the two-hour runtime of 'Sonic the Hedgehog 2' are you ever blindsided or confused by what's going on. Knuckles being voiced by Idris Elba and playing him like an Arthurian knight on a noble quest? Absolutely, totally makes sense. Jim Carrey yucking it up like it's 1995 all over again? Completely normal. Adam Pally just riffing his way through scenes without a care in the world? Of course. Despite what you might think in reading all this, the level of ease in 'Sonic the Hedgehog 2' works in its favour.
Nobody is really looking to edge themselves out here. All of the takes are probably the first or second ones, and you can feel the relaxed energy from all of the live-action performers. James Marsden is able to give his dad-friendly advice to Sonic in one reasonable take, smile broadly, and move on to the next one. Indeed, Adam Pally makes a reference to 'Ghostbusters' and it has a similarity after a fashion. 'Ghostbusters' - the original one, we should clarify - was done by a group of actors just going through the motions, not really giving a crap, and enjoying their company together. Yes, the results of this ease became comedic legend, but to them, it was just another job and done with relative comfort. 'Sonic the Hedgehog 2' isn't going to be on the same plane of existence as 'Ghostbusters' in a few decades, but that sense of relaxed, good-natured performance is really evident.
Is it a cinematic masterpiece, worthy of praise and critical reevaluation in ten years' time? Most likely not, but it owns its okayness at every step of the way in such a way that makes it quite enjoyable. It's a sequel movie about a talking blue hedgehog. What are you really expecting here, after all? The jokes are aimed more at kids, but parents can get a few chuckles here and there - Jim Carrey referring to the Mushroom Planet as a "piece of Shiitake place", as one example.
You really have to admire both the writers, director and producers' commitment to just taking it all one step at a time, and never overtaxing anything or anyone at all. There's no burst of bigger budget on the screen, there's no desperate attempt to connect Sonic to other SEGA characters. Nobody's looking out to see if 'Streets of Rage' characters are going to burst onto the screen, though you can see some familiar imagery from your childhood. Tails' red bi-plane, for example, features in the third act, but it's not done with such grandeur and weight that they have to park everything and let it take up time. The pacing and the flow of the movie just keeps the gags going, the action flying, the quips quipping, and all of it just so agreeable.
With a third one all but guaranteed - and teed up in a mid-credits scene - it's quite possible that it may run out of speed eventually, but for now, 'Sonic the Hedgehog 2' is breaking into its stride.