Making a Hit Tower Defense Game: A Top App Dev Interview

Pablo Ruiz
Alvaro Azofra, Co-Founder of Ironhide Studios.

Alvaro Azofra, Co-Founder of Ironhide Studios.

Welcome to the first article in the new Top App Dev Interview series!

In this series, we will interview the best of the best mobile app or games developers that have recently nailed a hit in the top charts of the App Store.

Each interview will be focused on one Top Developer who will tell us his inspiring story and share valuable tips and insightful information on how they made it to the top.

These guys know a lot, so try to read each of their answers and learn the most you can from them!

For our first interview we have Alvaro Azofra, Co-Founder of Ironhide Game Studio, makers of the award winning tower defense game, Kingdom Rush (App Store Link).

Keep reading to learn what Alvaro and Ironhide Games did to make Kingdom Rush such a hit – and their advice for what you can do to make a hit of your own!

History of Kingdom Rush

Learn tips from the makers of popular iOS game Kingdom Rush!

Learn tips from the makers of popular iOS game Kingdom Rush!

Can you tell us how Ironhide Game Studio started and how you became involved in Mobile Games?

Ironhide Game Studio started as a flash indie game developer in 2010. Pablo, Gonzalo and me always had a passion for games and decided to try and get into flash games. We all come from the IT industry and web development, so flash was a tool we knew how to use and that’s why we started with it.

We later moved into mobile since it was something we had as a goal. Start with flash games, and if everything goes well then move into mobile, that was our plan. Kingdom Rush was the game that opened up the door for us (or forced us) to get into the mobile industry.

Kingdom Rush started out as a Flash game, correct? How many people worked on the original Flash version of Kingdom Rush, and how long did it take to develop? How was the transition to iOS?

Yes Kingdom Rush started as a flash game and quickly became the best rated game on several of the leading flash game portals. Development of the game took around a year, half the year we worked part time and the last half, full time. The team was just Pablo, Gonzalo and me. Pablo would take on the role of programmer, Gonzalo on illustration, and I was on game design and jack of all trades (sound fx, story, game texts, level design, etc).

The transition to iOS was pretty fast: the game was doing great on flash, so taking it to mobile was the smart next step, and so we did. Development took around 4 months, in which not only we ported the game, but Pablo also had to learn how to code for iOS, which I believe was quite a feat!

How did you come up with the concept for such a game?

It wasn’t by chance. Before Kingdom Rush, we released another game called Soccer Challenge, a trivia game for facebook. Although the game was pretty nice, it was a commercial failure, the problem? we made a game without learning the market in which we would publish. (Rules are different on facebook as are on each platform)

This is a truly award winning game!

So we got back to flash games for portals. This time we would study the market a little bit: and we learned that strategy games were the games that got the highest bids from sponsors, so for that reason alone we chose to make a strategy game.

Then during brainstorming of the game, someone suggested a tower defense… and we all got a little scared, given TD’s are very popular and the market was saturated with them. Still we started brainstorming ideas, and one thing that we wanted to make differently was to give it more action.

On most TD games the players makes the strategy and then sits back to enjoy the show with minimal intervention, we wanted to change that, we wanted to make the player feel involved, busy, and wanted the stage to feel like a battle was going on. This led to many of the concepts and mechanics of the game and we really liked several of the ideas we had so we just took a leap of faith and got into it.

What challenges did you encounter during the development of the game?

Well too many to count! I think Kingdom Rush (flash) was the game that made us learn how games are developed, we had to learn game design, optimization, learn to program several different things we never did before, animation on a small scale, inventing how to balance a tower defense game, etc… everything was a challenge, because for us it was all uncharted territory and the project was huge with a lot of moving parts and things to learn. It was a great experience!

Then when taking it to mobile, we faced a whole new set of challenges, specially the memory issues and screen aspect ratios, and also the marketing challenges associated with publishing on mobile that is very different than flash.

Can you tell us what exciting new games are you working on right now? Are you going to tap into other game genres?

The next game will be a new chapter for Kingdom Rush that we expect to release in a few months (we don’t have a release date yet). This new adventure will take place south of the kingdom, on the untamed lands. A new evil is rising there and the player must stop it at all costs, fighting all new enemies through deserts, jungles and even the underground! We will be adding a new arsenal of towers, new and improved hero characters, all new enemies, new boss fights, a lot more fun stuff and the same quality gameplay as before.

About other genres, we’d love to, but for now it’s time for more Kingdom Rush. :)

Marketing and Advice

Kingdom Rush has expanded into other Realms!

A lot of indie developers struggle to get their games noticed and most of them never make it, can you tell us how you managed to stand out of the crowd?

Well I guess part of the credit goes to the fan base. Releasing on flash allowed us to create a huge fan base, because the game became very popular. On top of that we worked with publisher Armorgames that promoted the game to the whole audience of its game portal and made a marketing campaign.

All those factors, combined, helped the game stand out and become feature by Apple on release… then, gladly people on mobile liked the game as much as they did on flash so word of mouth and good reviews did the rest.

Kingdom Rush has been in the Top 100 spot in the App Store during almost its entire lifetime, can you share any tips or tactics you used to achieve such feat?

I think keeping the game on the top 100 is because we never stopped working on it. We kept on updating and improving the game, and we noticed that every time we made an update the game would go up back in ranks… people would get back to the game to see the new content, sometimes we got featured again, so there was extra exposure… and that brings new users. So updating and improving the game was key on keeping it in the top 100.

What advice do you have for aspiring games developers wanting to get into mobile game development?

Well lots of! But most importantly to make a game that they would love to play! Do not try to make the next big thing, just do your own thing, put a lot of love into it, have fun doing so! Making a good game is the most important, the rest, will come on its own.

Where Would You Like To See This Series Headed?

And that concludes our first Top App Dev Interview. A huge thanks to Alvaro and the entire Ironhide Games team for contributing!

If you are an app developer with a hit app or game in the top 100 in the App Store, we’d love to hear from you! Please drop us a note anytime.

At this point, we’d like to ask you where you want to see this series headed. What sorts of things would you like us to ask about in the future? Are there any requests for particular developers you’d like to hear from? Please join the forum discussion below!

We hope you enjoyed this interview, and that you take Alvaro’s advice to heart and build a game you would love to play!

Note: Do you want to learn how to make a Tower Defense game like Kingdom Rush? Check out our How To Make a Tower Defense Game tutorial, written by this very same author of this article! :]

Pablo Ruiz is a full-time mobile software developer and entrepreneur. He helps companies increase their profit by generating ideas, advising them and developing mobile apps and games for them through his company, InfinixSoft. Pablo is also the author of Cocos2d for iPhone: Beginner’s guide. To learn more, check out his LinkedIn profile. Pablo loves to talk about technology and games. Follow him on Twitter!

User Comments

8 Comments

  • I was wondering if we can learn more about the technology that they used for their game such as which game engine they used, what was the most challenging part in the implementation process.

    Thanks.
    lionserdar
  • @lionserdar: Thanks for the comment! So, you say you'd like to hear more on the side of the development of the app, more than anything else?
    Pabloruiz55
  • Thanks for the interview, Pablo and Alvaro, and thanks for Kingdom Rush! It's definitely my favorite tower defense game!

    There's a lot of good info in this article. I liked the point about continuing to update the game. Kingdom Rush is very polished and no doubt that contributes to its success.

    I have a few questions for Alvaro:

    You said you learned a lot about gamed design, and you did a great job! Kingdom Rush is really fun and balanced. Can you recommend some good resources (books, blogs, etc) on game design? Or was it all trial-and-error?

    How does the Flash version compare to the iOS version in terms of users and revenue? Would you recommend Flash as a good place for developers to start their games?

    What kind of monthly revenue are you seeing? If you don't want to give specifics, are you making enough money to support the three of you? Have you hired anyone else?


    I'd love to see interviews with other successful developers. It's very inspiring!

    Thanks,
    David
    dnorcott
  • Was the iOS version coded with Obj-c? or was it Adobe AIR?
    GameViewPoint
  • Thanks for a good article! I find the "non techie" stuff interesting too!
    I do not care what language or methods they used to build their game.. I want to hear the kind of stuff you get out from this interview :)

    job well done!
    Hannu
  • Great interview.

    Personally I think that interviews should be more about the person that the code, otherwise, why bother interviewing them at all? I like to find out where their ideas came from, what motivated them, what they are going to do next ...

    Colin E.
    ColinEberhardt
  • Hi!!! Thanks for the interview!
    I can answer some of the questions

    How does the Flash version compare to the iOS version in terms of users and revenue? Would you recommend Flash as a good place for developers to start their games?

    iOS version give us a lot more revenue than the flash version. We still believe that flash is a good way to start because is way less competitive as Mobile.

    What kind of monthly revenue are you seeing? If you don't want to give specifics, are you making enough money to support the three of you? Have you hired anyone else?


    I cannot give you the numbers, but YES...kingdom Rush help us to make a living on this and now we also have 8 more people working with us. So Kingdom Rush give us enough money for that.

    I was wondering if we can learn more about the technology that they used for their game such as which game engine they used, what was the most challenging part in the implementation process.


    We use cocos2d. The most challenging part in terms of programming was porting the game and learn Objective C in 4 months (port and learn).

    Was the iOS version coded with Obj-c? or was it Adobe AIR?

    Obj-c

    Best,
    Pablo
    pablo
  • Thanks for the great Interview! This was really insightful.

    I agree with Colin that the interviews should be more about the person than the technology used.

    Greetings,
    Katrin
    kphilipp

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