Enemy is Your Friend: Combat Design in Jade Ninja

Jade Ninja is an action arcade game featuring Japanese-style stages and settings released on iOS. By illustrating some examples of the design of Jade Ninja, I would like to share my thoughts about how to successfully create enemy characters for a combat-intense game and hopefully it could bring inspiration for your game.

First of all, let me give you some basic ideas about the gameplay of Jade Ninja. It is an endless runner game, however, different from the typical runner games you know, such as Temple Run or Jetpack Joyride. Although they are awesome games, Jade Ninja is nothing like them. In most endless runner games, players play the role as the protagonist who evades obstacles to escape from danger. In Jade Ninja, however, you play the role as the protector who must defend the protagonist, Ninja Girl, from chasing troops, which means that Jade Ninja is a combat-centric game, rather than an evasion-focused game. The most crucial key in a combat-centric game is the design of weapon and enemy. People loves utilizing mighty weapons, as long as there are various challenging enemies for them to deal with.

In Jade Ninja, enemy units will be chasing from behind and players have to eliminate enemies by swiping fingers on them, however if players adopt the same strategy as they did in Fruit Ninja, they would simply swipe arbitrarily to stop enemies, and which will result in becoming a boring game. To illustrate the high precision skills of Ninja, we introduced the energy mechanism which means each swiping will cost energy points, and players can’t issue any attack once energy goes down to zero. As you can imagine, a real ninja must act wisely, attack precisely and manage his/her energy carefully.

To spice things up in combat, we implemented 3 types of weapons: Katana, Blade and Spear. Katana is the swiftest weapon to use, however it deals enemies the slightest damage. Blade can break enemy defence and cause great damages, but consumes lots of energy. Spear can pierce through multiple enemies in one swipe and therefore very helpful to deal with multiple enemies. Players need to learn when to switch from one weapon to another strategically according to the enemies surrounded.

The character to be protected runs towards the right side of the screen, whereas enemies are chasing behind from the left side. Once enemies approach close enough, they will start attacking the protected one.

However, if every enemy character is desinged to be appearing and approaching in the same way, players can focus solely on the left and easily swipe their fingers on enemies there.

That’s why we design the assault types of enemies which will be jumping over from the roof, popping from ground and so on to surprise players and to pull their attention back to the right side of the screen.

Moreover, we put flying types of enemies in the game not only to offer enemy variety but also to enhance level design. Regarding the designing of space partition, enemy units are primarily categoried as Infantry, SWAT and Air Force to show up from every direction on the left side of screen.

Every enemy unit has different attack scopes ranging from melee, middle and long distance.

Since some enemies can parry your attack from Katana or Spear, you have to change weapon to Blade to break their defence, as mentioned previously.

There are some kind of enemies who can summon minions or split themselves up into two parts. The most efficient way to eliminate them is to attack by Spear.

Watch out the innocent people! While enemy units are coming from the left side of screen, there will also be innocent people running from the opposite. The real ninja won’t hurt innocent people -- if you hit them accidentally, you’d failed. In the meantime, fast-moving Ninja Monkey might come with innocent people. By any chance you bust the monkey, you could collect a lot of coins from it.

To balance between risk and reward is usually the most interesting part in game design.

In addition to specific scope and space, some of enemy units have their own perks too. Totally we implemented 30+ types of enemies, including 5 tough bosses for players to challenge. The process of designing various enemies with different behaviors is full of fun and indeed a challenging task.

Since Jade Ninja is free to be downloaded now, you might have an interest to try it out. Let me know what you think about it and hopefully I shall share how to balance the predefined set and randomness in level design next time.

Enjoy the fun of slashing enemies as blisteringly as a hot knife through butter!