The Kingdom Rush series has been a mega success on mobile and desktop platforms, keeping a tight grip on the tower defense market since 2011! Ironhide didn’t find success by accident, they followed some common sense principles of game development that the rest of indies can learn from.
Ironhide’s first two games were completely unsuccessful. If you played either of their games, you’ll see that the developers followed a watered down version of the four principles we’re going to talk about today. To reach success with their 3rd game, Kingdom Rush, they doubled down on how faithfully they follow these rules of thumb, and expanded the game’s scope which let their work shine through more.
- Game always balanced and each level is a new challenge
- Extreme attention to detail and very polished
- Great visuals, sounds, and voice acting
- Iterate, iterate, iterate
Ironhide spent 6 months full-time working on Kingdom Rush as a small indie studio in distant Uruguay. Before deciding on what game to work on, they studied the markets at the time. It didn’t take much research to figure out tower defense was a HOT genre, but they had to investigate their other options too. At that point, they only had enough savings to work on one more game, or else they’d have to call it quits. Tower defense was saturated at the time with very recently published popular games, but they went for it anyway – it was high risk high reward. High risk because it’s hard to break through a saturated market – whether that’s the iOS App Store, posting to Hacker News, or getting to the top of the TD genre. It’s high reward, because the saturated markets are the biggest… #1 spot on iOS App Store will net you $150k a day MINIMUM, #1 spot on HN gives you 25k page views. Kingdom Rush has been the king of TD, and their revenue is disgusting.
Kingdom Rush on iOS has pretty much never left the top #100 for US games, and stayed in top #100 US overall for many months after release. They weren’t making 150k a day… but it has definitely been quite a bit!
Sponsorship netted them: 30k exclusive license + 30k funding for iOS + 50/50 revenue share + free hardware + 20k from Kongregate.
#1 Always challenge the player
This is the tenet that keeps Kingdom Rush fun. They crafted each level to be a new challenge to the player. Almost every level, the player is introduced a new tower, enemy, mechanic, or some upgrade to their existing tools (towers + spells) that creates a new nuts strategy. In Poker, the nut hand is the strongest possible hand in any given situation; having ‘the nuts’ means having the nut hand. In Kingdom Rush, because new pieces of the game are always being introduced, the nuts change too.
Basically, a big part of the Kingdom Rush game loop is that the player has to reconsider his strategy every level. Maybe he’ll start with what worked last game, but there’s a good chance that that will fail or barely pass. Kingdom Rush brought many new strategy elements to Tower Defense packaged in one game – and they balanced their effectiveness (strengths & weaknesses), and how often they are introduced to the player.
The lesson of this tenet is the classic “keep your players challenged”. However, game developers must consider what tools are available to them to adjust the difficulty. I’m sure many of you remember having played, or even created a game, where the difficulties were just enemy difficulties scaled up or down! Easy was enemy health at 50%, and hardest was enemy health at 200%. I always hated difficulty mechanics like that. Kingdom Rush kept the player challenged by always introducing new elements to consider when forming their strategy; they layered strategy elements!
#2 Obsess over the little things
This tenet requires a fair bit of patience, but the player is really going to see it in the small interactions the player has with your game. Some environment in the game is interactive, units and towers say unique one-liners, all the transitions and pop-ups are perfect… You see where I’m going. Having an extreme attention to details should be noticed by the player as an absence of criticisms, and an “ooh!” or “cool!” in some cases, like with clicking on the environment. The “ooh!” moments are special moments between the player and the game; it’s like they’re having a little bonding time together. Let your players have many moments like that while playing your game and you will have a true fan, because they found unexpected bits of fun from your game, and they will remember that for a long time.
#3 Eye and ear candy
Your game has to look good and sound good… well usually. If the game is fun you don’t need anything else… but you probably won’t win any awards like that unless you’re still trying to write a Telnet MUD. If your game has everything else going for it, having great visuals and sound is what’s going to send it over the edge.
Let’s talk about voice overs. Something specifically pointed out in interviews and reviews are how great Kingdom Rush’s one line voice overs are. It’s something so simple, yet so well done, that they alone give a lot of character to the game. It’s just one more thing that makes players feel more attached to the game. To bring the point home, think about how famous some games, even decades past when they were released.
“Work work, something need doing?”
“My life for aiur!”
or even League of Legends, where all of their champions have a variety of quotes. “Skar skar… Skarner!”
These voice overs took very little work compared to the rest of the 6 months the team worked on the game, yet it’s a polish item that is specifically mentioned in articles about the game. Polish matters! When polishing your game, consider what work will have the most impact to the quality and success of your game.
#4 Keep iterating!
Ironhide had 3 test runs during their 6 months of development. Their first test run came a few months into development, the alpha to 20 testers soon after that, and then for months… nothing! They had an echo chamber for a while. After getting sponsored, they had their publisher, ArmorGames, release it to a small portion of their playerbase as an open beta. For a week, Ironhide collected tons of metrics from each play session. At the end of their open beta, they had data points from over ten thousand players, which they used to tweak everything in the game. They spent an entire month tweaking and polishing!
Kingdom Rush Reviews
You can get Kingdom Rush Frontiers for free from IGN. It may only be available until the end of June.