Hal has been inconsistent in terms of his personality, with different media showing different depictions of the character.
In multiple instances, like the Angry Birds Comic Series, Hal is shown as a very mature character. He is shown to have a deep love for the pleasures in life, as when he is found he is usually with his banjo or camping. He is a rather adventurous bird, and in Angry Birds Go, he wears an adventurer's hat (which was included in promo art and the game toys and telepods) He finds no desire to be filled with anger and usually doesn't take place in any of the bird's fights with the pigs.
However, in situations like the Summer Pignic short movie, or The Angry Birds Movie, Hal is shown to be an extremely clumsy and goofy character. He is clearly much younger, and in place of a raspy, creaky voice he is given a squeaky, nasally one. Unlike his other, much different personality, this version of him has an extreme desire to become angry and fight the pigs, along with being an actual "angry" bird.
Hal makes his first appearance in Angry Birds, where, unlike most new birds, Hal is first introduced as a captive by the pigs in Danger Above 6-4. After you beat the level, the game will notify the player about Hal's unlock, and he is then playable in the next level, Danger Above 6-5. Hal is then held captive in a separate cage from the other birds in The Big Setup, and is saved by Terence in The Big Setup 9-5, becoming the only other playable character in the episode.
Hal's ability in the game is arching into the opposite direction when activated. In order to do this, he opens his beak to resemble a boomerang. Due to this, he is much floatier than other birds and can fly much farther; this also makes him the only bird who rotates when airborne in the original game. Hal's ability will also be affected depending on the angle that he is in; for example, if he begins to gravitate back to the ground, his ability will weaken more and more.
A strategy players may use, which is also used to collect certain Golden Eggs, is to fling Hal backwards and then activate his ability, causing him to swing back with speed and more strength.Hal is quite decent at destroying wood and glass blocks and will do so extremely well if the blocks are somewhat damaged. However, he will not affect stone in most situations, usually making minimal damage or, in some circumstances no damage at all.
Angry Birds Seasons
Hal appears from the very start of the game when it was once known as Angry Birds Halloween. He is introduced in level 1-13 and is the very last bird introduced in this theme. After his appearance in Trick or Treat, he makes recurring appearances as a playable character in all of the following themes.
Unlike the rest of the installments in the Angry Birds series, Angry Birds Seasons does not update Hal's design to his newer one and stays true to the original.
Hal's ability is identical to the one in the original game. There are no major changes or differences in his size, strength, or speed. However, it is notable that when you fling Hal from the slingshot, his launch noises are much more different than the ones featured in the regular game.
It can also be noted that Piglantis introduced the feature of water and that Hal's ability is completely useless underwater. If the player attempts to activate Hal underwater, then he will instantly turn into a corpse and float to the surface.
Angry Birds Rio
However, after his first appearance, he manages to appear often in the Rio 2 segment of the game. He is introduced with his newer design, which included no yellow ring around his beak and a generally slimmer appearance.
Hal is not included in any animations or trailers for Rio. (excluding gameplay trailers)
In Rio 2, all the characters are given their animation designs, and Hal is drastically changed as well. He is given a black and green body, with a yellow eye-ring. His beak is also enlarged, being around 3 times larger than his actual body. It also now has a red streak going down it. It can also be noted that when his ability is activated, his beak will be so opened to the point where Hal is actually shaped like a boomerang.
Hal's ability is the same as the previous 2 installments of Angry Birds. However, unlike Angry Birds Seasons, Hal's ability will positively react with water and will work properly.
With moving boss fights, Hal will make minimal to decent damage when he comes in contact with the boss. In most boss fights he's in, there are usually collapsible structures that only he can reach, making him an advantage to have when you want to defeat the boss.
Angry Birds Friends
Hal appears in tournaments as a playable character for Angry Birds Friends. (first appearing in level 18 of Surf and Turf or the Tournament depending on player choice) In the Facebook version, he is also included in the Surf and Turf, Pigini Beach, and Pig Tales themes. (he will not appear in the other themes, as he hadn't been introduced as a character when those themes were first released) Hal is also featured in the shop as an unlockable avatar.
Angry Birds Friends was then updated with newer designs for all the characters in the game. (excluding Bubbles) Hal is the only character whos design wasn't based on their toons design. Rather, he was yet again given newer sprites, that featured a green body, a yellow eye-ring, and a large, curved beak.
Hal's ability is exactly the same as in the other slingshot based games.
If you bought the add-on Golden Slingshot, it will not have much effect on him. He will be able to destroy more glass and wood and destroy/damage a few/one stone brick(s). If you use the Diamond Slingshot, then his ability will be affected. When you activate his power, he will change direction, but will not be affected by the angle of the shot since the Diamond Slingshot will cause all birds to fly in a straight direction.
Angry Birds Go
Hal is featured as a playable character in Angry Birds Go. As all the characters had to be converted into 3D animation for the game, Hal took no exception. He takes on his animation style from Angry Birds Toons. (though he never appeared) His personal kart is the Shoemerang. (which costs 1,500 gems)
Hal is first featured in Stunt as the first boss. Previously, you had to beat him 3 times in order to unlock him; in these boss battles, he would throw boomerangs at you as a diversion. However, currently, you will be able to unlock him after getting one star on campaign level 9, race 5. Once you unlock him, he will be permanently playable.
Hal also appears in races as an opponent in all themes of the game.
His ability while being player-controlled is to send a tornado to all the karts racing in front of him. The tornado is also able to collect coins, fruits, and destroy obstacles that lay in front of him. His ability is fairly powerful and can be used to gain many places.
Angry Birds Transformers
Hal appears in Angry Birds Transformers and is given his first counterpart character. (having been the only member of Red's flock to not have one at that time) He is shown to be a dinosaur/motorcycle hybrid.
In the comic adaptions for the game, it is shown that Hal fell onto the eggspark (along with Chuck, who had unintentionally pushed him), and that is why he had first turned into Grimlock. This also makes his easygoing, peaceful, and friendly personality turn into mindlessness, and the will to fight.
As described in the game:
"You might call Grimlock the 'strong, silent type,' except he's really not silent at all. He loves to roar and smash and stomp and zap things with his laser and do anything else that's noisy. Grimlock doesn't like authority or taking orders (unless the order is to smash stuff up), but in the end, he always comes through for his team-mates. Grimlock is strong and brave, but also slow and clumsy. His direct, 'smash anything that gets in the way' attitude makes him an excellent asset on the battlefield, just don't expect him to do anything sneaky. But what do you expect? He's a dinosaur."
His ability can be used to destroy certain blocks by tapping on them, or, you can sweep your finger around the screen and he will follow with his electric shock. Either method will cause pulsing, bright electricity to shoot out of his mouth.
Grey Slam Grimlock is perhaps the weakest of all of Hal's counterparts, and the easiest to unlock. This version of him belongs to the "Leaders" squad. Energon Grimlock is very strong but will end up taking more damage. He belongs to the "Energon Fuelled" squad. Goldbite Grimlock is also very powerful, but is a variant character, belonging to the "Variant Versions" squad. Thus, if you fail a mission you will lose all coins from your missions.
As Trypticon, he is very different than other Grimlocks. He fires three to four black holes at a time similar to Megatron. Trypticon acts like a Deceptihog (Because Trypticon is based on a Decepticon). He belongs to "The Cybertronians" squad.
All 4 characters will transform into a motorbike in vehicle form.
Angry Birds Action!
Hal appears as a very minor character and only shows in the Wheel of Fortune section of the game Angry Birds Action!.
Angry Birds Ace Fighter
Hal appears in Angry Birds Ace Fighter as a non-playable character, and only appears in the loading screen and Bird Launcher section.
Strangely, while all of the other birds use their Toons animation style, Hal's design is based on his updated original style.
Angry Birds Holiday
Hal made a notable appearance in Angry Birds Holiday and owned his own purchasable item from the store. It is known that the game was made with 3D animation and that Hal used his Angry Birds Movie animation style in the game.
The game was never released outside of soft launch, and Rovio announced that the game stopped development. It was shut down as of December 21st, 2016.
As the game was never given a worldwide release, not much is exactly known about it, or Hal's involvement. It is known that his item, the "Adventure Club", could be bought with in-game currency, unlocking Hal in the process.
Angry Birds 2
When Angry Birds 2 first launched, it was stated by Rovio that Hal chose to "sit out" of the game, along with Bubbles and Stella. However, Hal was added to the game on December 6, 2018, as an extra bird.
The game also introduced computer animation for the birds and the pigs, which had never happened with the previous installments of the series. (which used pre-set separate sprites for when the bird is idle, flies, etc) Hal got a new Toons design and animation style, along with a new voice.
He also appears as icons that can be selected by the player as his profile picture.
He got a new design, that is based on his movie and classic design, only with dark green feathers, completely yellow long beak, black eyebrows, white belly, black tail, dark green rings surrounding the eyes and he has no hair, like the Toons design. In the player's icon, he uses the same design as his toons design and classic one.
Hal can be chosen as an extra bird, but for it, he has to sleep for 12 hours and used for 4 hours. He is strong but has to be used correctly, in order to make greater scores and damage.
When launched, Hal, unlike the other games, won't start spinning, instead, he will keep in the same way as the other birds. When his ability is activated, he will start spinning towards the structure, and will destroy blocks and defeat pigs in good strength when he has momentum, even destroying stone unlike the other games, where he gets injured after hitting stone, he will then get injured as he hits a solid object.
Angry Birds Evolution
The Angry Birds Movie
Hal makes a very minor appearance as a supporting character in the Angry Birds Movie and is voiced by Anthony Padilla. He is shown to be a very goofy, clumsy bird and takes part in the battle with the pigs.
To see Hal's involvement in the movie, see here.