The Making of Dirk Dashing 2

Following the release of my classic-style platformer, Dirk Dashing: Secret Agent!, I knew I would have to produce a sequel one day. The game was my second-highest seller, and it quickly developed a small fan base. I regularly received e-mails asking for new Dirk Dashing adventures, and I already had several potential storylines floating around in my head.

Still, the first Dirk Dashing game met with mixed reviews. People enjoyed the hand-painted, 16-layer parallax backgrounds, but they didn't like the flat character art and sparse building interiors. Also, I had built many cartoon gags into the game, like allowing players to trick enemies into running into walls, off ledges, or into each other, but these features went largely unnoticed because I didn't make them discoverable enough. So the game was criticized for not having enough weapons or ways to take out enemies. Before I could produce more Dirk stories, I knew I had to deal with these issues.

There were also features I wanted in the first game but didn't have time to incorporate. And I had lots of suggestions from the customers and fans to make the game better. So I wanted to address these too.

All of this drove the design for Dirk Dashing 2.

I. New Features

First, let's take a look at some of the game's new features. As you'll see, a lot of work has gone into this sequel.

New Graphics

For the sequel, I utilized the improved graphics engine from my 1950s-style space shooter, The Adventures of Rick Rocket, to provide richer graphics with lighting effects and shadows. I redrew all of the character art to apply cel shading and add greater detail. And I painted a much wider variety of building interiors, drew dozens of furniture pieces, and created lots of little details for the game backgrounds. As a result, Dirk has never looked better!

Improved Audio

Dirk Dashing 2 uses a new interactive audio design that integrates the music and sound more tightly with the gameplay. First, the music has been tied to the story. Instead of just looping music repeatedly, the game transitions between music pieces as plot developments and game events occur. And to fill the times when there may be no music playing, our musician Jesse Hopkins created various ambient sound loops and new sound effects for game objects that previously had no sound. I've also implemented a simple 3D positional sound system, so any object that emits sound will gradually fade in/out based on its distance from Dirk. Previously, I was turning off the sound for any object that wasn't on screen. But now you can hear the pop of wall-mounted gun turrets in the distance, the faint footsteps of an approaching enemy, etc. This creates a richer audio landscape for the game.

Second, we've assigned a new material property to every floor surface in the game. The material property indicates whether it is made of stone, wood, metal, carpet, dirt, etc. Jesse recorded a bunch of different footstep sounds for each material, which I tied directly to the animation for Dirk and other game characters. So as they're walking or running around, you'll be able to hear them. This way you'll know when an enemy is approaching before you ever see him.

Third, I beefed up the AI so that the game characters can "hear" your footsteps and movements too. Guards and enemies can hear Dirk running, landing after a high jump/fall, and shooting. They can also hear fellow guards cry out, explosions that occur nearby, and more. Having enemies react to what's going on around them makes the game world feel more "real".

New Stealth Tactics

One of the features that players enjoyed from the original game was the pseudo-stealth elements, like the ability to sneak past an enemy while his back was turned. I've played up the stealth aspect for the sequel by adding security cameras, laser trip wires, and other obstacles that players must sneak past undetected. If Dirk trips an alarm, all enemies become awake and alert, new enemies pour into the level, and parts of the level may get locked down - making it more difficult for Dirk to complete his mission.

I've also beefed up the AI so enemies can both see and hear Dirk. To compensate, I've added new stealth tactics that players can use to tiptoe past enemies or sneak up on them. One of Dirk's new gadgets include a set of night vision goggles that allow him to see in the dark. Dirk's enemies can't see him if he turns out the lights. Many levels include light switches that gives players full control of the lighting system, so players can turn lights on/off at will. This gives Dirk a distinct tactical advantage. However, enemies can still hear Dirk, and they'll shoot blindly in the dark at anything they hear but can't see. To compensate, players can hold down the Shift key when moving left and right to make Dirk tiptoe quietly.

In addition, enemies now have the ability to flip switches. Some enemies, especially if they are with a comrade, may choose to run for the alarm when they see Dirk. This means that players will have to plan their moves carefully and not just charge headlong into a room full of guards. 

Players who sneak through a level undetected can earn huge bonus points at the end of the level, so I think the addition of the stealth elements adds some wonderful dimension to the gameplay and really plays up the secret agent theme.

A New Weapon

Some players complained that the gas grenades from the first game were hard to use. Dirk throws them in an arc, and it can be tough to aim when you're under pressure. So I've designed a new weapon for Dirk: a tranquilizer dart gun.

I debated for a long time whether or not to give Dirk a gun. On the one hand, I felt like a gun would not only be an easier weapon to use but also add to the game's spy theme. On the other hand, I know the fans really appreciate the fact that Dirk doesn't kill his enemies. I definitely did not want to break the "no killing" rule that I made when I first started making this series of games. So after doing some research, I settled on a tranquilizer dart gun. Like the gas grenades, it is non-lethal and will put Dirk's enemies to sleep. But it should be much easier to use. It shoots darts in a straight line across the screen. However, unlike the gas grenades, they do not travel beyond the edge of the screen.

Of course, Dirk still has gas grenades in the sequel. They're useful in many situations, because you can throw them offscreen, you can toss them over barriers, and you can bounce them off walls. And there are some tougher enemies that have a shield, armor, or thick skin that the darts won't penetrate.

New Inventory System

While players enjoyed the gadgets in the first game, they didn't like the way you used them immediately when you picked them up. They wanted to be able to use them later. So for the sequel, I've added an inventory system for Dirk. Players can now pick up multiple weapons and gadgets, carry them along, and use them whenever they want!

I've built the inventory system into Dirk's new PDA, called the iSpy. It includes 5 slots for keys, and up to 10 slots for other items. You can use the arrow keys to select a new item from Dirk's inventory. You can also use the Tab key to change items without bringing up the iSpy.

New Health System

Dirk Dashing 1 was modeled closely after one of my favorite DOS platformers, Commander Keen. Like those games, Dirk died instantly if he touched anything harmful. But I quickly discovered that players nowadays prefer their games to be a bit more forgiving.

So for the sequel, I implemented a new health system. Now Dirk can take multiple hits before dying. I added health kits to the game to restore one point of health, and several large hearts that Dirk can find to increase his total number of health points.

New Moves

Dirk's moves in the first game were limited, so to mix things up, I added several new moves for the sequel. First, Dirk can climb ladders. Second, Dirk can hang from wires and pipes. He can shimmy left and right along the wire, and either let go and drop, or jump off the wire. This adds some variety to his moves, and opens up some new architectural possibilities for level design.

Multiple Skill Levels

Dirk Dashing 2 includes the addition of 3 skill levels. This was added in response to feedback from pre-order customers. Some felt the game with all of its new features was too easy, while others felt it was too hard.

I didn't want skill levels that just added more health points to enemies. I wanted skill levels that made more significant changes and resulted in a different gameplay experience. So I added an Easy skill level in which standard guards will never shoot (even if the alarm goes off). And I added a Hard skill level, in which guards always shoot on sight (even if the alarm hasn't sounded). Enemy placement and type also differs between skill levels. As a result, players on the Hard skill level will really have to make extensive use of the new stealth tactics to get through the levels. I think this adds a lot to the replay value of the game.

II. Producing the New Game Art

I've already mentioned the improved graphics, but I thought you might like a closer look at how I created some of the new graphics for Dirk Dashing 2.

Lighting Effects

The lighting effects proved to be very challenging. OpenGL lighting models were designed with 3D games in mind, but Dirk Dashing is a 2D game. We do some things with the game art to make it look pseudo-3D (for example, the floor looks like it is on a different plane than the fence), but it is really 2D. The 3D appearance is an illusion provided by the artwork design. Under the hood, the level background is essentially just a 2D tile map.

It took a lot of experimenting to get the lighting right, as you can see from all the failed attempts below. I tried a lot of different techniques, using per tile lighting, reversing the triangle direction depending on which side of the light source it was on, using smaller tiles, etc. But I finally discovered the right combination of lighting parameters and triangle orientation to get it working just right.

But the final result turned out pretty good:

Cel Shading

Applying cel shading to the character art has made a tremendous difference to the visual quality of the game. Looking at the picture below, on the left is the original drawing of Dirk from the first game, and on the right is the new drawing. I've applied cel shading to add some extra detail to the drawing and give it some depth. I've also added a shadow to help anchor Dirk to the ground. Both of these things help Dirk look much better with the new lighting effects.

It takes a lot of time to add all of this extra detail to each animation frame for each character, but I think the results are worth it. Here are some before and after pictures of other characters from the first game who return for the sequel:

Creating a Video Camera

One of the new features in the game is the security camera. Cameras will be posted throughout many of the levels, and Dirk will have to avoid being seen by them or risk setting off the alarm. I had some trouble with the animation for the security camera as it pivots back and forth - it was difficult to get good movement using hand-drawn graphics. So I got creative and built a little model.

I taped three old video cassettes together, covered them in a paper mockup, attached a pin on the bottom for a pivot point, and plotted the angular movement on an old manila envelope (which provided some good contrast with the white "camera" model). I set up my camera on a tripod and positioned it so it looked down on the model at just the right orientation that I wanted. Then I photographed a sequence of pictures with the model oriented at each of the angular positions.

Next, I downloaded all of the still images into the computer, converted them to black and white line art, and painted them.

The result is a security camera with smooth animation and a realistic path of movement. It looks pretty cool in the game! And it only took one day to do it all!

A friend of mine, who is a fellow game developer, saw this when I posted it on my forum and told me on Facebook: "Nice one, Troy. lol You're like the MacGuyver of video game production." Haha! Sometimes you just have to get creative to solve a problem...

Conclusion

As you can see, I've put a lot of effort into improving Dirk Dashing 2 and making it better than the original. I hope you enjoy the game!