Continued from part 1...
The first pig to design was the standard normal pig. No special abilities, nothing extreme, just toss and move on. We figured pink was a good color and gave him a mean scowl.
The drill pig was a character that had been thought of very early on and is unique to the game. The idea was to make a pig that you could shoot straight into the ground and he would travel through it just as any other pig would fly through the air. Gave him brown skin to give the appearance of mud and everyone seemed to like the drill hat idea.
The ghost pig was one of the favorite ideas on the team - a pig that would be transparent until you tapped on the screen to make him solid, essentially used to get past unbreakable barriers. The design for this one was fun, but a little complicated. I had the idea to give him little ears that would slowly wiggle back and forth in a ghost-tail kind of way, while also making the whole bottom part of his body also wiggle. The programmer and I worked out a way to put those sections of his body on separate layers that could be animated while attached to the whole image, all while his body would slowly float up and down.
The jetpack pig went through more revisions than any prior character, and at one point we debated dropping him altogether, though I'm glad we kept him because he's definitely the most fun pig out of all of them. The jetpack pig's power is that you can constantly and infinitely change his direction in midair just by tapping on a different spot on the screen. He'll keep flying around wherever you tell him to until he makes contact with an object and then his jetpack blows up and he falls to the ground like any other pig. He's also got a spunkier personality and his facial expression changes alot more drastically than any other pig.
The next pig was the most debated character in the game. We wanted a pig that you could tap to give a speed boost and hit something harder (much like the yellow bird in Angry Birds). The question became, what force does he use to propel himself? The yellow bird in A.B. doesn't have a reason to go faster when you tap him, he just does. Why would our pig go faster? I drew up all sorts of sketches - pigs getting struck by lightning, pigs farting, pigs with propellers on their backs - I tried to justify the propeller with either a metal body, or dress him up like a coal miner... for some reason... Neither design stuck for very long.
For a while, we thought about having a pig that would pull out a hang-glider, but logically, that wouldn't make something go faster, just farther. We even thought about switching roles with the jetpack pig and giving him just a 1-time extra boost and making the hang-glider the multi-directional character. Eventually, the design I came up with was sort of a happy accident. I had started doing full-screen, realistic illustrations for the game and in one of them, I had drawn a pig with a cowboy hat in a kind of western duel setting with a bird.
Weeks after I had made that drawing, we suddenly realized that we could use that cowboy design to give the appearance of a pig who would have a gunshot-reaction when tapped to propel himself forward. Thus, the cowboy pig was created for in-game use.