At nine years old, Jefferson Johnson of Vienna created, designed and helped develop the game app “Treehouse Wars.” Now 10, he has raised enough money to build an upgrade. (Tom Jackman/The Washington Post)

You want to play a fun new app on your iPhone or iPad? There’s a kid for that.

The kid is Jefferson Johnson, who begins fifth grade today at Flint Hill Elementary School in the Vienna area of Fairfax County. At the ripe old age of nine, he devised the concept and then developed (with some help from Australia) the game “Treehouse Wars.” It’s a sort of humanized version of “Plants vs. Zombies” in which a swarm of aliens attacks a boy in a treehouse, and the boy must fend them off with water balloons, frisbees, bowling balls, boomerangs and other stuff you can acquire as you rise through the 30 (!!) increasingly difficult levels of the game.

Jefferson then got his game into the Apple App Store, where you can download it for free, but he wanted more: more weapons, more protection for the treehouse, and to fix some minor bugs. So he launched a Kickstarter campaign to try to raise $1,000. And within a day, he had $1,200. He will soon begin working on his “legendary upgrade package” for Treehouse Wars.

“It’s good,” Jefferson said of his game, in which he admits he has only gotten to Level 29 (!!!). “I might make more games, we’re not definite about anything yet.” And by “we”, he means himself and his brother Talmage, 8, with whom he co-founded his company Candy Wrapper Inc. two years ago. His father, entrepreneur Bryan Johnson, was an initial investor, but is now insisting that Jefferson take more responsibility for both fund-raising and creative control within the company.

A screenshot of “Treehouse Wars,” in which aliens besiege a poor lad in a treehouse who is armed only with water balloons, smoke bombs, bowling balls, frisbees, boomerangs, anvils (!) and tornadoes (!!). (Screenshot)

Jefferson, who turned 10 in June, explained the genesis of Treehouse Wars by saying that “me and my Dad have always been wanting to do projects together. We did robots. But it was either too hard or Dad did all of the work. Then one day, we were thinking of ideas and we thought of an app.”

Jefferson is not an overly tech-oriented kid: He doesn’t have an iPod Touch, as many his age do, and he is limited to three one-hour computer game sessions a week, as many his age are. But he certainly knew what an app was, and his dad knew of a website called Game Salad, which allows anyone to produce a video game for free without much coding knowledge, and produce a really good video game for $299.

“We wanted this to be a kid-based app,” Jefferson continued. “We had to think of what kids would like. We came up with the idea of treehouses, kids like treehouses. So we put that in the app. Then we had to think of what weapons we could use.” And that evolved beyond standard projectiles to smoke bombs, anvils (H/T the Roadrunner) and tornadoes.

Johnson didn’t want to be the one to do the heavy lifting again. “I wanted him to learn how to do it,” he said. So he went to, where freelance computer experts offer their services, and found Luke Allen, a 23-year-old programmer in Melbourne, Australia, who agreed to tutor Jefferson for $20 an hour via Skype.

Beginning in February, the two Skyped twice a week for about 90 minutes per session. Allen said it was thoroughly enjoyable.

“Typically, clients have an idea of what they want in their mind but often can’t articulate it to me,” Allen said in an e-mail. “Jefferson was the opposite which was very refreshing. He had no problems explaining exactly what he wanted but if we came to the conclusion that one of his ideas wouldn’t work he would just drop it and move to the next one straight away. It was amazing!”

The pair worked together for about three months. “It’s pretty hard,” Jefferson said. “They use all these big words that I don’t really know,” such as “interpolate” and “X axis” and “Y axis.” Jefferson and his tutor both logged into the same website so they could work on the project simultaneously while 10,000 miles and 14 hours apart. “As I watched him do it,” Jefferson said, “I figured it out.”

“Jefferson was great,” Allen said. “He would come up with these incredibly creative thoughts for the aliens or the weapons in the game and then I would try to think of the best way to implement them without influencing his decisions too much. We left quite a few ideas on the cutting room floor due to either time constraints or because in the end they simply didn’t work as well as we hoped, but it never seemed to bother Jefferson. His ability to prioritize and readjust his thinking on the fly was great.”

Then came the beta testing, which involved Jefferson’s friends at Flint Hill, his brother, his three-year-old sister Genevieve, even some adults. “As we all know, kids are extremely honest critics,” Allen said, “so it felt good when we got it right. They were a tough crowd to please.”

In addition to my own testing, which was incompetent, I allowed two boys I know, ages 10 and 7 1/2, to play Treehouse Wars and they loved it and will resume their quest for Level 30 whenever I let them have my iPhone again.

By May, it was ready and in early June it was approved by Apple for the App Store, first on iPad, then on iPhone in July, both for free. And that’s when Jefferson launched his Kickstarter campaign, seeking $1,000 to fund his upgrade, including money to pay Allen. “I told him I’d fund him in the beginning,” his father said, “but he’d have to chart his path going forward.”

Word of Treehouse Wars apparently had spread through the tech world by mid-July. In 24 hours, he had topped $1,000. “We’re going to start building the upgrade next week,” Jefferson said, and it will cost 99 cents when available. He promises an “ultimate weapon” and may even draw some of his own graphics, including a blond-haired boy in the treehouse this time, which might just resemble him.

Here’s a clip of what the game looks like now, before the “ultimate upgrade:”