I've played all of the mainline Ratchet and Clank games except the PS4 reboot, and I'm going to be honest I think this is my least favourite of the bunch. Now, I don't think it's a bad game exactly, there's a lot of effort that's gone into this thing and in particular I think that the core gameplay verbs of run, shoot, jump are as good as they've ever been, but I've just finished up my first playthrough and I have to be honest with you: I kinda feel nothing for Rift Apart.
I think that this feeling comes down to two main points:
1) There's no meat on them there bones
2) The story has nothing to say
So, for point 1, an easy way of looking at it is that the game only features 9 planets. Each one has a main story mission, one significant side activity, and then maybe a resource gathering thing if you're lucky. Compare that to my personal favourite Going Commando, and that has like 20ish levels (depending on if you count the ship levels), most of which have two main paths and sometimes optional side activities. This would be understandable if Rift Apart levels were big and sprawling, but in my opinion they are not. Torren IV is like a couple of islands of fighting and then an overproduced grind rail section - not exactly an inspiring return to the planet where we met Azimuth of all people.
Ok, if Rift Apart doesn't have quantity, maybe it has quality? Eh, not really. Even though core gameplay is really fluid, it's been great since A Crack in Time, and that game was longer, had more interesting Clank levels, challenge moons, ship combat... Going Commando has so many gameplay modes that I don't know how they fit it all in (sadly, probably crunch): run and gun, ship combat, clank levels, hoverbike racing, glider sections, giant clank, multiple arenas, multiple open world collectathons. Sure, most of them weren't that fleshed out or balanced (hello Y.E.T.I hordes) but they broke up the main gameplay in a way that made the game feel really dynamic. Rift apart has run and gun, really short rift challenges, clank levels, and Rivet's dragon buddy.
Also, what's up with the weapon upgrades? The weapons themselves are a decent selection that remind me of Deadlocked in how nicely they combo into each other, but the final upgrade for each one failed to make a noticeable difference to their gameplay. Half the fun of Ratchet and Clank is seeing all the cool and weird weapons, so having them change only subtly at level 5 was a big letdown. As an example, compare the Glove of Doom in this game to the version in Up Your Arsenal: I could not tell you what the level 5 glove of doom does differently in this game because it is still just chucking out 4 or so little snapper robots that beat up the enemy for you. Meanwhile, in Arsenal, the little robots get guns and jetpacks as they level up, turning essentially a cluster homing bomb into temporary orbital turrets. That was rad!
So, now we have point 2. It's not like Ratchet and Clank is known for their amazing narratives, but I feel like they at least had something to offer in this department. The PS2 games have a sardonic sense of humour, and each one takes aim at some facet of modern society: celebrity sponsorships, corporate espionage, media conglomerates, etc. The Future games toned down the attitude quite a bit, but they focused more on Ratchet and Clank as characters, with A Crack in Time specifically giving them wonderful arcs as they shake off the expectations of the past to look ahead to their futures together.
Rift Apart has the unenviable task of writing a story for two characters who have already had multiple bigger and smaller character arcs over the course of like 20 years. The way it gets around this is by introducing Rivet and Kit, alternate universe versions of the characters who get to serve as a fresh start, and then they give them a watered down version of the cliff notes of Ratchet and Clank's story. Great job guys. Rivet starts the story as a selfless heroic type, but oh no, she doesn't like working with others. Except she warms up to Clank in the span of one conversation. And she works with the Morts back home on Sargasso all the time. That's the theme of the writing in this game in general: A character states their archetype explicitly (this may or may not be supported by the rest of the script), they have one conversation with someone else on the cast, and then they immediately fix one of their character flaws. Job's a good'un, let's all go home folks. I dunno, maybe I just outgrew the writing for this style of entertainment; I guess I'm not in the target demographic any more.
So yeah, in conclusion it's a decent enough product, but honestly I feel no better for having played it. I doubt I'll be thinking about it in 20 years time like I still think about blowing up the rockets on Todano in Going Commando or firing the Harbinger in Deadlocked for the first time. Play Rift apart if you've exhausted every other 3D platformer or third person shooter on your list.
A character design as good as Rivet deserved a better game.