YOU NEED AN DUAL SHOCK PS1 CONTROLLER TO PLAY THIS GAME. IT WON'T WORK WITH THE ORIGINAL PS1 CONTROLLER.
Now that that's out of the way: this is a great 3D platformer for PS1. This game uses both analog sticks in unique way (Left stick moves, Right stick is used to control gadgets) that although weird at first, quickly feels intuitive when you consider how the game works. The camera, often a sore spot for early 3D platformers, is above average here. It usually works. The graphics are bright and colorful with an anime feel to the characters.
The levels are well thought out and only very rarely have annoying sections imho. Music is great in this game too. There's something to be said about the fact that whenever I spot an ape in this game, some part of my brain lights up with joy at the thought of snatching him.
If I had to point out some negatives I'd say...well, the camera isn't perfect. Also, some people might not like using the R1/R2 to jump. Oh, and every time I try to use a paddleboat in this game I can't quite get the motion of the sticks right and it becomes kind of a joke. But it's a joke I can laugh at because...this game is charming.