This is one PS2 game that I will keep forever.
Now that you heard about the graphics, let's talk about other points. The gameplay is revolutionary (for its time at least) and is loads of fun with plenty of stuff to do. I like travelling to different planets and the weapons and gadgets are so cleverly designed and fun to use. The Suck Cannon is quite a cool gun which you use to suck inside tiny enemies and shoot them as cannonballs at bigger foes. The slingshot is cool and so are the grind boots (for sliding) and magneboots (magnetic obviously) and even the hyrdo pack and the thruster pack. There are litterally dozens and dozens of these sorts of stuff so you get a lot of things to entertain and help you through.
Linearity has been very commonly mentioned in video games nowadays especially after we experienced games like Star Wars: Knights of the Old Republic, and Neverwinter Nights. This is a story-driven game, but fortunately it is not a 100% straight game. You can sometimes choose which infobots to look for (robots which you give you co-ordinates to unlock a new planet to travel to) so it gives the game rather good replay value.
The story is actually pretty good in my point of view, with a clever plot. The characters are brilliant (not to mention Ratchet and his robot sidekick; Clank). Chairmen Drek is a perfect villain and Captain Qwark is a hilarious character. The story has a lot of humour (not only cutscenes, but even the suck cannon info mentioned before) so it is definitely a joy to experience. The sound is great. I have mentioned music in a lot of my game reviews since I see it as one of the biggest points in a game so I will mention it here. Each planet has its own unique song, or songs, which you hear as you play through it (or parts of it if it is more than one song). Each of them are a joy to listen to. I can't believe I did not try to search for the soundtrack yet. The composer (or composers) each deserve an award for that. Its a pity that he (or they) did not recieve one. That definitely proves the flaws that award voters have in themselves.
Everything about this game is good. Every planet, every weapon and gadget, every character, every song, every everything is very well thought-out. Don't be fooled by the 'TEEN' rating it recieved. This game is for all ages to enjoy, which means that no matter how old you are, you should get this.