It's not good.
Game-development has trended away from my preferred genres over time, and playing this in 2024 has inflated the relative quality of this game.
I like the genres represented here: platformers and STGs are, of relative intensity, represented in Stewie's sections, Peter gets the beat-'em-up portions, and Brian gets some straightforward stealth-gameplay. None of these are executed in particularly fleshed out or polished ways, and it's not fair to expect them to be since these 3 types of gameplay should be the sole focus of 1 individual game and not all be part of the same game. Though, the dev should be blamed for including the 3. It's an ambitious undertaking, and, even if all 3 were executed to perfection, the game shouldn't be alternating between them. They have to be this simple by necessity since they're all here. The game was doomed to fail by their simultaneous inclusion.
Stewie's sections are the best. They have the most variety and polish, and I imagine they got the most dev-time. He's got a double-jump, a glide, multiple charged shot-types, an upgrade-system, and a very deliberate sliding-mechanic. There's also a context-sensitive grapple-mechanic, but, aside from latching on for some optional collectibles, it basically just moves you to point B for free with no strategy behind it.
Peter's sections are next best. Enemies and objects are susceptible to a variation of attack-types and combos. Some enemies only take damage from punches, some only from kicks, vehicles only take damage from the head-butt combo, etc. He's got a meter that builds from item pickups, and allows use of a few special attacks. The early game spin-kick does high enough damage that it'll clear crowd-fights in 1 use, and can even take out the entire health-gauge of most boss-fights. His tackle knocks enemies over, and downed enemies can be picked up and thrown to instantly kill them and any enemy (enemies?) hit by them. The final super attack seemed to do high damage, but it's rare that you'll have the time to get it out in an actual fight due to its high-charge time. A spin-kick can usually achieve the same effect instantly.
Brian's sections are the weakest. Even as a fan of stealth-games, they're simplistic to a fault. You have an extremely limited set of options for manipulating "guard" patrols. There's a gauge that fills when they see you that leads to being caught as opposed to just instantly being seen, and you can briefly appear in their sight-line to stop them in place. I didn't personally find a use for this in my 1 run. The other option is to interact with a context-sensitive prompt that'll automatically move the guards somewhere else for you with no other input required from the player. You have a variety of disguises (cosmetic in terms of variety, not function) that just cause "guards" to ignore you, or not be able to see you when you're standing still. You have a simple crouch that allows Brian to hide behind walls or get under objects to hide. The last gimmick are objects that cause Brian to take control of the player to waste time with the added penalty of losing whatever disguise is equipped until Brian enters shadows. Shadows make Brian undetectable to all "guards". That sounds like more than it is, and there isn't a single section that puts it all to use at once.
The cutaways return in the form of minigames. They're sometimes placed at incredibly inopportune moments, like the beginning of a difficult section right after the checkpoint, but they're typically worth winning. Stewie's especially for upgrade-parts, Peter's vary in usefulness (they give meter, so it depends on if you need it or not), and Brian's give temporary invisibility (sometimes let's you skip entire sections, sometimes doesn't do much).
This game was not worth playing in 2006, but I'd take it over the majority of today's AAA releases. That opinion is based on what I grew up playing and my own sensibilities, and definitely may not apply to you. Again though, it's not good. Just good enough to finish. 2/5
Game-development has trended away from my preferred genres over time, and playing this in 2024 has inflated the relative quality of this game.
I like the genres represented here: platformers and STGs are, of relative intensity, represented in Stewie's sections, Peter gets the beat-'em-up portions, and Brian gets some straightforward stealth-gameplay. None of these are executed in particularly fleshed out or polished ways, and it's not fair to expect them to be since these 3 types of gameplay should be the sole focus of 1 individual game and not all be part of the same game. Though, the dev should be blamed for including the 3. It's an ambitious undertaking, and, even if all 3 were executed to perfection, the game shouldn't be alternating between them. They have to be this simple by necessity since they're all here. The game was doomed to fail by their simultaneous inclusion.
Stewie's sections are the best. They have the most variety and polish, and I imagine they got the most dev-time. He's got a double-jump, a glide, multiple charged shot-types, an upgrade-system, and a very deliberate sliding-mechanic. There's also a context-sensitive grapple-mechanic, but, aside from latching on for some optional collectibles, it basically just moves you to point B for free with no strategy behind it.
Peter's sections are next best. Enemies and objects are susceptible to a variation of attack-types and combos. Some enemies only take damage from punches, some only from kicks, vehicles only take damage from the head-butt combo, etc. He's got a meter that builds from item pickups, and allows use of a few special attacks. The early game spin-kick does high enough damage that it'll clear crowd-fights in 1 use, and can even take out the entire health-gauge of most boss-fights. His tackle knocks enemies over, and downed enemies can be picked up and thrown to instantly kill them and any enemy (enemies?) hit by them. The final super attack seemed to do high damage, but it's rare that you'll have the time to get it out in an actual fight due to its high-charge time. A spin-kick can usually achieve the same effect instantly.
Brian's sections are the weakest. Even as a fan of stealth-games, they're simplistic to a fault. You have an extremely limited set of options for manipulating "guard" patrols. There's a gauge that fills when they see you that leads to being caught as opposed to just instantly being seen, and you can briefly appear in their sight-line to stop them in place. I didn't personally find a use for this in my 1 run. The other option is to interact with a context-sensitive prompt that'll automatically move the guards somewhere else for you with no other input required from the player. You have a variety of disguises (cosmetic in terms of variety, not function) that just cause "guards" to ignore you, or not be able to see you when you're standing still. You have a simple crouch that allows Brian to hide behind walls or get under objects to hide. The last gimmick are objects that cause Brian to take control of the player to waste time with the added penalty of losing whatever disguise is equipped until Brian enters shadows. Shadows make Brian undetectable to all "guards". That sounds like more than it is, and there isn't a single section that puts it all to use at once.
The cutaways return in the form of minigames. They're sometimes placed at incredibly inopportune moments, like the beginning of a difficult section right after the checkpoint, but they're typically worth winning. Stewie's especially for upgrade-parts, Peter's vary in usefulness (they give meter, so it depends on if you need it or not), and Brian's give temporary invisibility (sometimes let's you skip entire sections, sometimes doesn't do much).
This game was not worth playing in 2006, but I'd take it over the majority of today's AAA releases. That opinion is based on what I grew up playing and my own sensibilities, and definitely may not apply to you. Again though, it's not good. Just good enough to finish. 2/5