The first completed project I’ve ever done in Unity. Before being invited to join the team I had literally no experience with the Unity engine. We only had 6 weeks of real development time, but we managed to make it work perfectly.

The Playground was a school project I did at the HKU. It’s a multiplayer first person shooter that takes place on a playground with fake weapons, making it completely kid friendly. Another unique thing about the game is that it uses a heartrate monitor to change the way you play.

The video was made with a pretty early version, but it shows the basic principle fairly well.

Working on the game was a real challenge. I was the only programmer on the team, after leaving another team where the other programmer would be able to do everything on his own. Without any experience I started on the obvious biggest challenge, creating a multiplayer environment reliable enough for a multiplayer shooter, while also learning the basics of Unity. The first thing I created was a small level with a single spawn point and a player class that was able to shoot instant-hit projectiles and a slow moving grenade. After this I decided how I wanted to implement multiplayer. With the small amount of experience I had gained at this point I started with a system that had a server that simulated the entire world, sending just the coordinates of each player, projectile and shot. This turned out to be a complete failure, since all players felt like they were getting hit when they shouldn’t and missing shots that were obviously on point in their client.

After my first experience with the multiplayer system I decided to do some research and experimentation, this quickly led to a much better system when it comes to the experience of the user. Every player would have their own movement and instant-hit shots resolved on their end, while the slow projectiles, their position and their speed would be sent to all other clients where the other player’s client would decide if it was a hit or not. This combination turned out to give the best experience, because players felt like they were in control of what happened to them. 2 weeks into the project this system was fully operational and players were already enjoying themselves just running around and shooting each other.

After this system was finalized the first art and levels were implemented which made the game feel a lot more alive. A lobby system was added and a master server system was setup, just to see how that would work, since we weren’t planning to actually release it. To give players a few more strategic options we also added a wooden sword as the first melee weapon.

Once the basic gameplay was done I moved over to the hardware system. The idea was very simple, we had found a USB device that would connect to a chest strap that could monitor the player’s heartrate. It was a simple serial device that could be polled about 4 times per second, giving it a pretty good response time and a highly accurate reading.

Nobody was actually working on designing the effects the heartrate would have on gameplay, so I decided to just implement something and see how people responded. My first idea was to have a high heartrate decrease the accuracy of ranged weapons, but this just wasn’t enough of an effect to actually impact gameplay too much, since there was no value in trying to control your heartrate. The second iteration was just an expansion on this idea, but actually moved the range in which heartrate affected accuracy down, so that it was below the average heartrate. This was better since people felt like they had to be very calm to be a sniper and if they got too excited they had to run at the enemy. The third and final iteration was based on that idea. Accuracy would still decrease as heartrate increase, but the player’s movement speed would also increase drastically, enforcing the idea that melee weapons and close range combat would be better at that point. A low heartrate would turn the player’s character slightly transparent and make him slightly slower. This transparency would allow a sniper to actually stay hidden. A fun fact about this transparency was that it went all the way down to fully transparent, at very slow heartrates.

This system created a unique experience where players would be actively trying to figure out how to control their heartrate, while also being at the mercy of their temper, since trying to calm down to disappear is a hard thing to do, but playing a multiplayer shooter while running in place to run faster isn’t easy either. Our favorite players were the ones that had extreme playstyles. A good example of this is a player that would start running in place while jumping every four steps as soon as he spotted the enemy or got shot at. He won and sweated a lot.