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The Explodemon Saga - Part Three

The third part of the Explodemon Saga describes how Explodemon’s various game systems were fleshed out and shows the first full draft of the finished prototype. The combat system is also described in detail.

[You can view the other parts of the Explodemon Saga here!]


When I came to implement crates, that mainstay of video game furniture, I kept coming back to Half-Life 2 and its gravity gun. Every physics object in Half-Life 2 reinforced the player’s knowledge of the real world; objects that were thrown responded as expected, and their interactions with other physics objects provided predictable rules that could be used to solve puzzles. Because the forces emitted from my game’s explosions had the potential to be a similar source of physics-based gameplay, I wanted to try to create the same sense of physicality, of destructiveness, of reliable and predictable rules, but in a 2D platform game.

Gravity is fun!

I therefore spent a while coding a (simple) physics system. Crates would respond to relevant forces in relevant directions when hit by explosions, bounce off other crates and so on. I made the objects move fast and land heavy, to emphasise the arcade-like direction the game was heading.

Following on from objects moving as expected, I felt it was important that the player enjoy every single explosion that they created, to make even the simple act of pressing a button be rewarding and moreish. I’m a big believer that if you make the lowest level of a game’s interface enjoyable, you’ve got a much better chance of building a rewarding game on top. To this end, I made lots of shit blow up into tiny pieces; windows, solid walls, wooden crates, areas of solid rock (completely stolen from Yoshi’s Island).

A big breakthrough came when I mimicked Half-Life 2’s time-delayed exploding barrels, by creating a crate that would itself explode after a period. A by-product of this was that the player could hit these exploding crates into other crates, creating chain reactions and destroying things at distance, purely by exploiting the properties of the physics system. The beginnings of a fun system that allowed for a good degree of player expression were beginning to form.

By now it was December 2005, and during work hours at Curve, we’d finished off the Superman joystick game and were almost there on the Spider-Man pack. We’d been speaking to a number of publishers, desperately trying to get a break back onto consoles, but we’d been confounded at every turn. The industry was still in a state of transition, and only safe bets (studios, as well as IPs) were being funded. Still, we’d been lucky enough to arrange another two joystick game packs to start in the New Year, so the worry of running out of work was kept at bay for the holiday season, a feat that we wouldn’t always manage in later years. Just before I was set to visit my in-laws in Australia for Xmas, I created a build of Explodemon, which shows the results of my ramblings above.

Xmas 2005 Build

The three week Australian trip, away from computers and games, ended up being a powerful catalyst for the productive period on Explodemon that would follow. Unable to implement any ideas, I built up a number of concepts in parallel, concepts that I was raring to get started on the moment I got in front of a PC. Due to my desire to create a polished platform game, I remember diving right into writing the definable keys, menu system and checkpoint code on my return, something I think my wife found a little strange!

Another contributor to the productivity of this period was the dire lack of need for creativity during my work hours. Early in January 2006, we’d begun production on two joystick games. The first was based on the excellent Avatar: The Last Airbender cartoon series, which I selflessly allowed Rudolf (Kremers, Eufloria) to do the design work on. I’d then left myself with the real dregs; the Thomas the Tank Engine joystick game. It’s not something I really want to go into in too much detail, but suffice to say that it was the worst project I’ve ever worked on, beset with major production hiccups that were outside our control. With all of that creative momentum building up, and nothing to fulfil it apart from my lunch time project, Explodemon rapidly began to take shape.

Combat was my first port of call. I created a really simple enemy by taking the crates, making them move left and right wherever they landed, and giving them sprite animations to match. Insta-enemy. After seeing how well the exploding crates turned out, I had the enemies explode when they ran out of health, but only when they came to a stop. This last part was key because it meant enemies could be used to create chained explosions by aiming them with your own – in other words, the enemies themselves could become weapons. Being able to then have these enemies airlifted in by Halo-style dropships was just total geeky empowerment for me.


Meanwhile, I’d had this really great idea about the combat; a mechanic that would keep every encounter interesting. My inspiration this time was the risk/reward mechanic used in Bangai-O’s special attacks. In Bangai-O, you squeeze one of the triggers to unleash an attack that fires multiple shots in all directions. The brilliant bit is that the attack fires off more shots the more danger you are in. It works on proximity, so the closer the enemy shots are to you – and the higher the number – the more powerful the special attack is when executed. Since all enemy shots are destroyed by the special attack, the aim is to wait until the very last moment when you are about to take a hit before pressing the special attack button to unleash a super powerful counter. It’s risk/reward in a distilled form, and is pure Treasure genius.

Because the player’s main attack in Explodemon was centred on their location, and Explodemon himself took damage if he touched an enemy, I took Bangai-O’s mechanic and applied it to the player explosion. If the player played safe and exploded an enemy while they were far away, they did little damage and got little reward. However, if they waited until the very last moment when they were just about to make contact, the explosion did massive damage and the player got a large reward.


Now, when I say reward, I’m not just referring to a glowing sense of self-satisfaction. It was important that this reward meant something - that players valued and desired it. To fulfil this function, I created Explosion Levels. The high concept for Explosion Levels was simple: the higher your explosion level, the more powerful you were. The ‘reward’ for defeating enemies were red orbs; the ‘better’ you defeated them, the more orbs you got, the higher your explosion level, the more powerful you became. The opposite of this was not defeating the enemies well, where leaving it too late to explode or just plain taking a hit would reduce your Explosion Level. So, a simple yet deep system worked its way into the combat:

  • Explode at the last minute to play well and get more powerful.
  • Mess it up and get less powerful until you eventually die.

Also adding to the strategy the player would have to form during the combat was the recharging gauge that had to be full before exploding. It gave a rhythm to the combat, with the player constantly alternating between two states. When the gauge was full, the player was capable and destructive – able to choose how, where and when to attack. However, once the explosion had been released, the player was now on the defensive, unable to strike back. While in this state, the player needed to skilfully dodge and evade attacks, manoeuvring themselves into the ideal position to attack again and, if playing well, coinciding this positioning with the gauge fully recharging. This system (along with the risk/reward explosion mechanic) was to be my take on Halo’s famous “30 seconds of fun”, and it has ensured that the combat in Explodemon has remained absorbing to this day.

For the defensive state,  where the player was waiting for their gauge to recharge, I needed Explodemon to be responsive and manoeuvrable. For this, I created the slide, which was a movement technique that the player could employ but not use offensively, instead lifting enemies and objects into the air and buying time and space. The creation of this move was also down to my longstanding dislike of the Mega Man games. I’ve never played more than 30 minutes of a Mega Man game to this day, because I find the abilities of the main character too limiting. I find the fact that he can’t crouch or shoot in more than two directions to be frustrating rather than enabling. He’s so immovable, and I understand why some people like the gameplay that the limitations create, but for me it’s like moving a brick around. I find it funny when people say Explodemon is inspired by Mega Man, because it’s true in a way that people might not expect: some of Explodemon is how it is because I wanted the main character to be nothing like Mega Man!

The final part of the combat puzzle was the counter. I used to play a huge amount of Street Fighter II and, to a lesser extent, Tekken. I’d always enjoyed the complexity afforded by the rule sets of beat-em-ups, and especially the idea of advanced techniques. These kinds of features bring depth and longevity for more committed gamers, and I wanted to add that kind of feature to the combat in Explodemon. I was inspired by the Alpha Counter and Parry systems in Street Fighter and also the Counter and Chicken system in Tekken. I wanted something reaction-based that would turn the tables for the player if they were in a tough situation, but only if they were quick enough and understood the game well.

And so, Explodemon’s own counter technique was born: if your explosion gauge was empty and you could not attack, but you were inside an explosion created by an enemy or other object, then you could ‘counter’ it. I saw this as Explodemon drawing power from the explosion he was in to create one of his own. It manifested itself as a half a second window within which the player had to press the explode button, indicated to the player by a [!] above their head. If you were quick and played strategically, you could repeatedly explode, quickly clearing a mass of enemies with panache.

With these systems in place, I created two levels in which to showcase the game. I also included a bunch of other mechanics, like the Metroid-inspired boost run, and the missile redirection mechanic. Created in March 2006, these two levels formed the main gameplay levels for the next three years. You can check them out in their entirety in these two movies.

  Explodemon Prototype - Level 1

  Explodemon Prototype - Level 2

In the next part I’ll look at how Explodemon finally bust out of its Game Maker prototype to become an internal project at Curve,and detail the response we got from publishers when we showed them what we had.

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