Happy Tree Friends Adventures

Happy Tree Friends Adventures is a fan game series created by radel999 (a.k.a. HTFMegaman). It's mostly a crossover with Mario, sometimes Megaman.

So far, it has 6 sequels and a spinoff.

Gameplay
The objective of the games is to save HTF's world from Bowser's threat by rescuing the world's princess (Giggles in the first sequel). The game itself is a 2D side-scrolling type with mainly enemies from Super Mario. Players can obtain gems for points, hearts for healing, and 1-UP items for extra life.

Before beginning a level, the player can choose one of the playable HTF characters. Once chosen, the player can't change his/her choice, even if the character had lost a life.

During the game, the player can jump, pick up items, swim, climb, and kill enemies. Normally, the only way to kill an enemy is by firing orbs at them (default attack). Starting from HTFA 6, the player can make use of a respective HTF character's special power, which can be used as an alternative attack, for breaking through blocked areas, to freeze an enemy, or to hit multiple enemies. In HTF Origins, the characters can stomp on certain enemies to kill them.

In order to finish a level, the player has to go through the level until he/she reaches the finishing spot. In some sequels, however, you'll end up meeting a boss per level. For boss-related levels, you have to kill the boss before you can proceed to the next level.

Happy Tree Friends Adventures
The objective of the game is to rescue Giggles from the hands of Bowser. Cuddles, Flaky, Petunia, and Nutty were the only playable characters. The game has some elements from Super Mario. It also contains bosses in certain levels.

Happy Tree Friends Adventures 2
This time, the objective of the game is to rescue the HTF's world princess. Giggles and Toothy are now added as playable characters. Each level is long and holds a boss.

Happy Tree Friends Adventures 3
It has the same objective as the previous sequel, but unlike the previous one the levels are shorter and bosses are only located in certain areas (the game has a map to show progress).

Happy Tree Friends Adventures 4
This game's mechanics have expanded this time. There are some levels that doesn't involve going on foot. Just like in the second sequel, each level is long and contains a boss at the end.

Happy Tree Friends Adventures 5
For this game, the tree friends' sprites are now different. But still, the objective remains the same. But instead of having difficult bosses in each level, Birdos are placed in almost every level's end. The main bosses are still located in certain levels though. More game mechanics are added, like the tree friends' ability to swim, climb, etc.

Happy Tree Friends Adventures 6
The tree friends' sprites are updated once more in this game. The game now has Megaman mechanics and enemies. Two extra characters are added, which are unlockable after you managed to access a certain event. The objective is still the same as well. However, more tree friends made their cameos, like Pop, Cub, Handy, Lumpy, and Flippy. There are also more villains like Lifty, Shifty, and Tiger General. As for the hidden characters, one is a fan character, while another one isn't from the HTF universe.

Happy Tree Friends Origins
This first spinoff doesn't star the 6 HTF characters as the playable characters. Instead, you have to play as one of two HTF fan characters. The objective of the game is to stop Bowser from summoning a deadly monster and to save the captured tree friends. Unlike the main games, this is the only game to show the characters being able to stomp on some enemies to defeat them. Also, unique power-ups are present in the game.

List of upcoming games from the series
This lists the games from the series that haven't released yet, but are in HTFMegaman's plan:
 * Happy Tree Friends Adventures Land
 * Happy Tree Friends Adventures: Fura Fura Power!
 * Happy Tree Friends Adventures Legends (also known as simply HTF Legends)
 * Happy Tree Friends Adventures 7: The Greatest Battle Ever (possible correct title, as the "Greatest" in this title is written as "Great" according to radel999)
 * Cuddles and Giggles: Rabbitcapade
 * HTF Adventures RPG: The Fire Point
 * HTF Adventures: Casey's Quest
 * Happy Tree Friends Adventures 8: The Daemon Conquest
 * HTF Adventures Island
 * Happy Tree Friends Adventures Deluxe (remake from the original HTFA)
 * Happy Tree Friends Adventures 3D
 * Happy Tree Friends Adventures (Gameboy style)

Games made by different people
This lists the games based on this series, but are made by someone other than HTFMegaman. So far, there's only one, which is '''Happy Tree Friends Adventures Re-Born: 2nd Strike! '''(on planning, isn't released yet).

Canceled games
This lists the canceled games in the series. They're used to be worked on by HTFMegaman but unfortunately he decided to give up working on them. So far, there's only one game to be canceled, which is Magical Flaky.

Trivia

 * Most of the games from this series are based on existing video games, like Super Mario Bros., Megaman, etc. Even the enemies and bosses are based on various video games.
 * This fan game series is notable for having bad grammar and typos. (ex: The "Choose Your Character" as shown during the character selection screen is written as "Choose You Character")
 * Starting from HTFA 4, the main characters have voices. In HTFA 6 onwards, all characters speak clear English.
 * Flaky has ears in the first 3 sequels of HTFA. They're removed starting from HTFA 4, though.
 * Even though that the whole game itself is a crossover, the sixth sequel of HTFA is the only sequel to have a non-HTF character to appear in HTF style.
 * Only the first and the third sequels are not playable, as their download links are down (both were uploaded in Megaupload).
 * During the early 3 sequels, players have trouble on firing the orbs when jumping, as the orbs are fired downwards rather than to the side and thus requires a slight movement to the right or left (depending on where to shoot).
 * If you listen carefully, most of the music used in the game are either from existing video games or a remix of those.