It has it's moments of fun, but when they're gone it's just annoying.
Ape Escape Academy is basically built around a lot of mini-games. You are a monkey attending the Ape Academy and have to win a certain number of games and make lines on a tic-tac-toe board, you win you get a O, and when you lose you get an X. Sometimes, if you're lucky, you can get a Review class to help you pass. But if you failed the game the first time, you'll most likely fail it again. It takes a total of 6 years (2 Junior years and 4 senior years) to graduate.
Unfortunately, 6 years is a very long time, especially with sometimes challenging mini-games. And you can win as many as possible, if it's not enough to graduate, you have to do it all over again, which gets extremely annoying even if it's just a careless mistake. Some games are easy, others are just plain impossible.
Another bad thing about the game, there are only about 10 games that are actually fun. The rest can just be irritating wastes of time that you will lose almost every time. But those 10 games are actually fun and you would want to do them a few times before you get bored and walk away.
Ape Escape Academy is a fun game at times. But the frustration that occurs when you lose mini-games and fail graduation make it harder and harder to come back for more.