First off, let me state that I have a long history with this game, so some of this may be influenced by nostalgia.
Anyways, Pac-Man World Rally is a very decent game. The overall feel of the game is quirky and cartoonish, which captures interest right away. Another thing I enjoy about this game is the character lineup. You have the main pac-family along with the ghosts, as usual, topped off with the antagonists from all 3 Pac-Man Worlds and even a character exclusive to this game, Pac-Devil. Along the way you'll also be able to unlock three characters from different Namco games, which is a nice touch to bring back the memories from other games.
This leads me into one thing I very much enjoy about this game: the unlockables. The way they laid out the design for unlockable features was great. You could unlock new tracks as the game progressed along with the new characters I mentioned and even unlock 4 extra power-ups. I really appreciated the power-up unlockables because they will add a new flavor to the game and, of course, it's a very unique idea.
There's one last topic I'd like to cover before I move on to the bad about this game: the music. The music is wonderfully composed for this game! I never pay much mind to the music of games, but this soundtrack really sticks out. Every song has its own unique sound to it that fits the track it's in gorgeously. More importantly, every song has a retro undertone somewhere in it. The most obvious being the "Cloud Garden" music, which has various pac-man sound effects in it coupled with familiar gameplay jingles all set to a rock sounding anthem. Even the blander racetrack "Pirate Cove" has a musical secret. The sea-shanty being played is actually based off the music from the Act II cutscene of the Ms. Pac-man Arcade game. Overall, the music is excellent.
Now onto the poorer parts of the game. My first complaint is a minor one, but it's still a problem nonetheless. The characters have little to no traits. Sure, they have different animations accompanying events, but they still feel very distant and impersonal, especially considering every character handles nearly the same. This problem could have been fixed a little if they'd added better voices to the characters. They have their own sounds, but it can barely be heard over the pounding music and the roar of engines.
My next complaint is the lack of quality game modes. There are essentially two modes to this game: Circuit and Battle. Circuit is just the main racing and Battle is where you equip your kart with creatively designed fruit weapons and fight to the death. There are two other modes, time trial and quick race, but they're essentially cut-and-pastes of Circuit mode with different options. Something like a mission mode or a better modified version of Circuit mode would be appreciated. By the modified modes, I mean something like relay races or follow-the-leader driving or even just a mirror mode. If not an option, even a couple extra tracks could have been added for longer replay value.
My third criticism is a bit more trivial than the others but still annoys me. The PSP version of this game got an extra track, two extra battle tracks, 2 new characters, and 2 new modes. Why weren't these included in the other versions? The extra track is amazing, fan favorite characters like Mappy were included, and extra options for battle mode and just new modes altogether would have made the other versions much better. The problem is the PSP version suffers from its battery life, its frame rate and its 6-player race limitations. Combining the salvaged tech specs from the console versions and the extra options from the PSP version would have been fantastic. Also, because this is too short to talk about at length in a separate point, some extra characters would have been nice. Adding extra members of the Pac-family like Professor and Baby Pac would have been cool, plus extra unlockables from other series like Goro from "Mappy" and heck, even the Rally-X Car from Rally-X would have added some extra detail to the game.
My final criticism that severely affected the game was the AI. The computer players are absolutely dreadful. Even on Nightmare mode a newcomer wouldn't have much trouble overtaking the computers. The main problems with them is that they have no rubber-band (the capability for AIs to go unnaturally fast to catch up to an experienced player). Most gamers hate this, but it keeps the game challenging but not frustrating for veteran players when used properly in games. Here they just go at their own pace regardless of what the player is doing. They also very rarely launch items, making a player in first place a shoo-in. Then there are the shortcuts, which only Nightmare players use and rarely at that. These shortcuts are very strategic tools but with no other players using them there's no contest. Especially considering the PC version has no multiplayer I'm aware of, I would suggest buying the console versions which allow you to play with friends.
So, overall, Pac-Man World Rally is a decent game. It has wonderful music and a fun theme, but a lack of things to do and horrible AI can sometimes suck the fun out of the game. I would recommend this game to anyone who is a Pac-Man fan or is simply looking for a good diversion game.