Knockout City Gameplay - Boomerang Ball
As a part of our ongoing seasonal content for Knockout City, we continually introduced new Special Ball types to the game. The Boomerang Ball was the first Special Ball that I was directly responsible for, and it was an interesting challenge. The Boomerang Ball's gameplay revolved around modifying one of Knockout City's key mechanics: when you throw a dodgeball, it will usually end up further away from you, and near the person you threw it at. The Boomerang Ball, on the other hand, returns to the person throwing it, giving you an opportunity to use it again.
At the most basic level, it does what you would expect: when you throw the ball and it hits something, it will "throw" itself back to you, allowing you to catch it on the return and get another chance to use it. This creates a very intuitive approach to it's gameplay (players have an immediate sense of what the ball does, and can start to understand it's nuances within a few throws), but it still had a variety of design challenges that had to be thought through.
First, we needed to come up with a set of rules for how the ball would return to players. Initially, the first pass of the ball would infinitely bounce on targets until it hit level geometry twice in a row. While this was certainly initially very exciting, it led to some very extreme behaviors. For example, if two players were in close confines with one another, the ball would hit one of them, bounce to the other, hit them, and essentially stunlock both players permanently. Unless another player came along to break them out of it, neither player could escape this. This behavior also increased the speed of the ball with each hit (using Knockout City's overcharge tier system) and could propel players further and further apart at extreme speeds. Interesting for game designers, not so fun for players.
To fix this issue, we settled on a simpler set of rules for bouncing behavior. If a Boomerang Ball hit something, it would bounce back, then if it hit that new target, it would bounce one more time, before becoming neutral. This ensured that we didn't end up with stunlocks, and put the onus on the initial throwing player to catch the first return, or risk giving the ball to their initial target.
Some additional issues to fix: the ball played well for players with good internet connections and higher hand-eye-coordination, but others tended to struggle catching the return throw. To alleviate this issue, we put in a small amount of delay on hit (so the ball would hover in the air for a couple tenths of a second) as well as slowing down the balls return travel speed. Additionally, we added a different set of visual effects and audio for the return trip, as well as a different border warning to ensure players understood the damaging version of the ball, versus the undamaging return version. Overall, slowing down the return trips made the ball much easier to understand, and cut down on detrimental chaos during intense matches.
Overall the ball was well received by the community. Internally, we worried that it might be too strong, especially in the hands of an experienced player, but the community seemed to enjoy it's launch state, so we left it as is until sunset.
Artists: Steve Buccholz, Kelsey Martin
