Saru Get You/Ape Escape (1999, PlayStation) - The first PlayStation game to explicitly require the use of the DualShock controller.
Saru Get You 2/Ape Escape 2 (2002, PlayStation 2)
Saru Get You P/Ape Escape: On the Loose (2005, PSP) - A port of the first game.
Saru Get You 3/Ape Escape 3 (2005, PlayStation 2)
Saru Get You: Million Monkeys (2006, PlayStation 2)
Saru Get You: SaruSaru Daisakusen (2007, PSP)
Pipo Saru 2001 (2001, PlayStation 2)
Gacha Mecha Stadium Saru Battle/Ape Escape: Pumped & Primed (2004, PlayStation 2)
Saru Eye Toy Oosawagi/EyeToy: Monkey Mania (2004, PlayStation 2)
Pipo Saru Academia/Ape (Escape) Academy (2004, PSP)
Pipo Saru Academia 2/Ape Academy 2 (2005, PSP)
Saru Get You: Pipo Saru Racer (2006, PSP)
Ape Quest/Pipo Saru Senki (2008, PSP)
Furi Furi! Saru Get You/(PlayStation Move) Ape Escape (2010, PlayStation 3)
The series is notable for its control scheme, where the PlayStation's symbol buttons change your myriad gadgets and the right analog stick uses them (also, R1 and R2 are used to jump).Spike appeared as a playable character in Playstation All Stars Battle Royale in his Million Monkeys attire, albeit with a more westernized look.
Art Shift: In Ape Escape 3, a few cutscenes will temporarily switch to 2D animation for reaction shots.
The anime is mainly animated in 3D but occasionally switches to 2D for emphasis or reaction shots.
The cutscenes in the PlayStation Move game. The protagonists look much older then the ones from the previous games. The overall style is less cutesy as well (except for all the monkeys, Specter himself is much cuter looking).
Million Monkeys has the weirdest ones, with about 50% of the cutscenes filmed in real life.
Blessed with Suck: In Ape Escape 3, after the 6th boss battle, it is revealed that Dr. Tomoki was a human test subject for the Pipo helmet, when a freak accident caused it to fuse to his head, resulting in his intelligence being multiplied approximately tenfold (if his claim of an I.Q. of 1300 is to be believed), but also leaving him with a ridiculous-looking light forever attached to his cranium.
Bonus Boss: There are two secret monkeys in Ape Escape 2 that only appear after completing the game and capturing all the monkeys in their respective levels. One is dressed in Mickey Mouse's Sorcerer's Apprentice getup and summons hordes of enemies while teleporting around the area, and the other is a cyborg who is faster than the other cyborg monkeys, more powerful than them, and takes several hits from the Magic Punch before the suit is destroyed.
Brown Note: The Specter TV broadcasts in the third game hypnotized everyone who watches it, including, conveniently, the protagonists from the past two games.
The Cameo: In 3, a few underwater enemies come straight out of the Japan-only Sony game Space Fishermen. It's even lampshaded in the description for one of the enemies, wondering if it's in the wrong game.
Camp Gay: Yellow Monkey. So much that he "flirts" with Kei, the male protagonist of 3. Also, Dr. Tomoki, to a lesser extent.
Colour Coded Characters: The monkeys all wear different colored pants, which hints at their nature when you encounter them in a level; yellow = basic grunts, light blue = cowards, navy = insanely-fast speedsters, red = aggressive fighters (and they gain the ability to block your attacks in 2), green = nimble monkeys who carry backpacks that fire homing missiles, black = machine-gun toting monkeys with A-Team Firing skills, white = oddball with weird quirks and poor eyesight due to their Nerd Glasses.
Except in the first game, where monkeys with white pants were exceptionally alert, and thus pretty much impossible to sneak up on.
Continuity Reboot: The PlayStation Move Ape Escape has a completely new story. The main character is a teenager Heroic Mime and his two sisters capturing monkeys from space, while looking for their grandmother too. The overall style underwent an Art Shift (although the monkeys themselves remain the same). The only returning character is Specter, and his backstory has been completely changed from a circus monkey corrupted by a intelligence boosting helmet to an already intelligent Woobie, Destroyer of Worlds after being forcibly launched up into space. While not horrible, most fans are hoping it doesn't stick.
Cool Helmet: The Peak Point/Pipo helmets the monkeys wear, which boost their intelligence.
Cool Shades: Black-pantsed monkeys wear sweet shades and carry submachine guns. Yeah, mankind is screwed.
Disc One Final Dungeon: Pulled twice in the first game. The first time is Crumbling Castle (see "Wham Episode" below). When you return to the present, you then have to deal with TV Tower, which is merely a front for Specter Land. In 2, you make it to Code C.H.I.M.P after defeating Red Monkey, only for Giant Yellow Monkey to crash the party, forcing Specter to retreat. You do get to confront Specter one level later on the Moon Base though.
Actually, three times. There's also the end of Specter Land: Monkey Madness. After this, you have to go back and capture all the remaining monkeys before the true final boss.
Jack of All Trades is played with, due to the choice of player character: Satoru's a sports-nut, which makes him the fastests of the two, while Sayaka is somewhat slower, but is blessed with a fan-base who got a few monkies in it. Besides that both play the same.
In one of the early levels in the first game (Dark Ruins), four of the monkeys are named after the kids from South Park. One of them is named "Cratman". Why they misspelled his name and not the others, nobody really knows...
Ape Escape 3 features a level that takes place in a hot spring. Depending on if the player picked Kei or Yumi, they can only enter the male or female section of the hot spring. In the male section, there is a monkey that is attempting to climb up a wall, likely wanting to sneak a peek at the girl monkeys.
Gotta Catch Them All: You only need to catch a certain number of monkeys in each level to advance, but to unlock the final boss fight, you need to capture every single monkey in the game.
G-Rated Drug: Vita-Z bananas, which apparently act like steroids with the side effect of total, complete insanity.
The Hat Makes the Man: The Hat Makes the Ape? All the apes (with the exception of Pipotchi in the second game) have their personalities altered by the Peak Point helmets.
Heel-Face Turn: At the end of the PlayStation Move game, upon being re-united with his owner Haru, Specter is more then happy to be with her and her grandchildren, and they take him home to give him a bath.
Heroic Mime: To a degree, Spike when you unlock him upon catching all the monkeys with Jimmy. He has lines, but no interactions with any of the characters.
The main character of the PlayStation Move game is this, to the point where his dialogue in the cutscenes is text only.
Monkey Behind the Monkey: The ending of the PlayStation Move game implies that the monkeys (who were descended from monkeys launched into space and eventually evolved and devolved into their current state) were behind the invasion of Earth on their own free will, not Specter's. They decide life is boring without him and invade Earth again and kidnap him.
Marathon Level: The final few levels of all three games are significantly larger than those that came before them. This actually corresponds with an increase in difficulty, as larger areas = more hiding places for monkeys.
Nintendo Hard: Several instances throughout the series, but the last level of the first game is particularly egregious.
No Export for You: Piposaru 2001, Million Monkeys, Piposaru Racer, and SaruSaru Big Mission were the only titles in the series to not get an English release. An Eyetoy entry in the series, Monkey Mania, never got an American release due to poor reception in Japan, Europe, and Australia. Ape Academy 2 similarly only got released in Europe and Japan. In an odd case, Pumped and Primed was not released in Europe.
All of the characters (except Specter) might be gone now, as the PlayStation Move game has a completely different storyline with new characters. We'll have to wait and see if they decide to continue this new story or not.
Repeat Cut: When you finally catch Specter in the first game, it's shown from three different angles.
Rewarding Vandalism: All sorts of things spew coins and energy (and monkeys, on the rare occasion) when you smash them to bits with your club.
Ridiculously Cute Critter: Pipotchi. Specter, when he's not under the influence of the Peak Point Helmet, is also quite adorable and huggable. He also looks like this in the PlayStation Move title, due to the Art Shift and being The Woobie.
Rival Turned Evil: Jake (named Buzz in PAL territories, probably to better fit "Spike") from the first game and Pumped and Primed.
Sequel Hook: At the end of the PlayStation Move game, the Space!Monkeys return to Earth and kidnap Specter. Tsukushi and Tohko inform tell their brother to go and rescue him.
Ship Tease: Between Spike/Kakeru and Helga/Haruka. Both the anime and Pumped & Primed make this very clear.
The anime also provides us with Jake/Hiroki and Natalie/Natsumi.
Shout-Out: The third game has quite a few, being based on movies and whatnot. Not to mention Mesal Gear Solid. Metal Gear Solid 3 returned the favor.
The 3rd game includes cheats the play has to input in the main menu and then load the game with the corresponding save that gave you the code. After that you will unlock different monkeys in different cameo clothing. Two of them are straight references to the first two games while one other is a reference to Rachet And Clank.
The previous games stuff them in the monkey and enemy descriptions as well.
Stealth-Based Game: Sort of. You have to crawl around to catch monkeys unawares, otherwise they'll run away and/or fire their weapons at you. But even then, it's entirely possible to catch most monkeys just by running around enough, especially if you abuse the hell out of the Super Hoop.
In Ape Escape 3, you can buy a minigame named Mesal Gear Solid where you play as a monkey-fied Snake trying to save an abducted Snake.
Both Ape Escape 3 and Metal Gear Solid 3 were worked on/released around the same time (Metal Gear Solid 3: Subsistance was) and they both decided: "Hey, let's make minigames based on eachother's games!" As stated above, Ape Escape 3 featured a Metal Gear Solid minigame and Metal Gear Solid 3 featured an Ape Escape minigame.
Wham Episode: Crumbling Castle. Though it seems like the last level, no sooner do you reach Specter and Jake before they ditch you, leaving you to fight an armored warrior. Then you get transported back to the present day where the monkeys are already in charge of the city and The Professor and Natalie have been kidnapped.
Also, when Natsumi and the Professor are kidnapped atop TV Tower.
The Wham Episode of the 3rd one happens twice: 1st is during the intro of the game, explaining why the new protagonists have to do what to do, while the 2nd explains a certain villians past.
Million Monkeys makes no attempt whatsoever to hide that it is a very different game than the rest. To put it into perspective, the Goliath mechas that serve as the Final Boss of the first two games were usually incomplete or flawed. In Million Monkeys, a boss fight against a fully-functional Goliath is the first mission.