I've never played it but i still have enough information to know about it well, despite it being considered great by people because it is Ratchet on the go or it is there first R&C game, it didn't aged that well as whole unlike the previous games,
Some of the characters notably Ratchet (albeit not as frequently) and Qwark have been flanderized, the former was a jerk for not believing Technomites exist until finding out later and the latter is like a manchild and barely has any funny or rememberable moments and feels almost like filler.
Otto Destruct (despite being the main villain) gets a very little amount of screentime and his actual plan isn't the same compared to his troops' intentions, it isn't really explained why he wants to be the most intelligent being and his status after defeat is unknown (probably ended up like Qwark early in UYA where he thought was a monkey).
Luna is a strange character to me, the fact that the Technomites used the concept of a young girl as a disguise is strange and her slight alteration as a Technomite robot is creepy (mainly because how her eyes turn red and small but she looks completely normal and jolly in her boss fight like it never happened).
To top that off, the game is pretty short as it only consisted of 8 planets and Ratchet seemlying ditched the Star Explorer in favor for a slightly generic one that's probably unnamed and most likely isn't customizable (despite it being cosmetic to the Star Explorer but it was really cool), i do appreciate that the franchise went to a slightly lighter tone after Deadlocked since then but Size Matters feels allot weaker honestly.