What’s the need for nonlinear PvP?

Hey! At Donut Lab we are working on a mobile shooter Donut Punks. From the very beginning, we were faced with the task of creating a game with an unusual setting and having an engaging competitive gameplay at its core.

However, many set this goal for themselves... Therefore, it was essential for us to find our own approach and come up with non-trivial solutions that could express the ideas inherent in our gaming universe.

At the heart of Donut Punks lore is the conflict between young heroes and zombie adults. The former embody spontaneity, freedom and ingenuity. While the latter stand for mediocrity and averageness. With a starting point like that, we couldn’t create a classic conflict between those two, since zombies right off the bat, seem weak and unattractive for the player. We also couldn’t see PvP based on the conflict of heroes. In our universe, the heroes are deprived of the hatred characteristic of zombies, and under no circumstances would they kill each other.

Therefore, we decided to create a nonlinear PvP model. Zombies have become mobs, and kids have become playable characters. As a result, the following damage model was formed for the battle: the players (you and your rivals) attack the zombie mobs, and they, in turn, go after the players. The winner is the one who collects the most loot from the killed zombies.

PvE Damage Model

Such a model resembled classic PvE, and players' interactions were flawed. And damage couldn’t improve that. That’s how the idea of nonlinear PvP was born, and that’s how perks came around. Perks are a set of unique abilities that allow you to either send your rival into the hands of mobs, or prevent them from collecting loot. And at the same time, perks do not cause damage.

Nonlinear PvP damage model

So, to attack mobs, players use weapons, and among themselves they only use perks. There is infinite ammo, but the "overheating" mechanics are in place. Magazines are full and constantly reloading if they are about to run out. In the case of perks, the traditional cooldown mechanics are used, so players have to wait some time before they can use any kind of perks again.

How does it work?

Let's take a look at a few specific perks to see how this model works in the game.

Perks are unique to each hero and show their character. Some of the perks are intended to slow down and stop rivals from what they were doing. For example, Sleepie, who suffers from insomnia, is able to put other players to sleep, and frostbitten Freezie, well you guessed it, freezes them. Pooper, anarchist and punk, blinds opponents by throwing mud. All these slow down opponents or completely incapacitate them, blocking attacks and all potential movement.

There are also more complex perks. Blogger Dizlike throws a magnet to steal loot from under the noses of other players. And hippie Chakra creates a peace zone, within which players lose the ability to use weapons.

In practice, these techniques can be applied in different ways. For example, the peace zone was initially supposed to be a trap. Chakra would throw a perk at the rival, so they would be locked up with a crowd of zombies and couldn’t attack — as a result, the character would die, unable to escape or fight enemies back.

But the players found their own use for this perk: instead of trapping rivals in the peace zone, they would find a place free from zombies and trap themselves inside. Zombies couldn’t get to them and ended up going after other players. That way, the players stayed safe and bought themselves some time!

This example is indicative: when you offer the player an unusual mechanic, be prepared that it will not be used as intended.

How to teach a player?

The nonlinear PvP system is extremely rare, and in this sense, Kids vs Zombies has almost no analogs. When our game went into beta, it became clear that players needed training on how to use perks and how to take advantage of them.

According to the statistics, we saw that players who managed to use 4 or more perks show RR1 ~80% higher than those who didn’t use them. That meant that the mechanics worked and caught on. But there was a problem -— those who didn’t manage to learn how to use just left! We began to solve this problem one step at a time.

Relation of RR1 and amount of times perks were used

Step #1. The first step was to add a loading tutorial screen to the game. The animation showed how to use perks and what their benefits are i.e. more loot, less annoying rivals, etc. Made sense, but it proved to be not useful at all! Users used perks once and forgot about them in the battles to come. Take a look at the graph below — version 933.

Step #2. Alright. Since we are making a game, why don’t we improve the gameplay? The first and simple solution is to increase the number of enemies in battle. As a result, zombies began to eat players who have been affected by the perk more often, and for the users themselves, this mechanic became a more visible part of the battle. As a result — slight growth. Check version 1090 on the chart.

Step #3. A start has been made! We continued to tweak the mechanics: now the zombies would aggro on players who have been affected by the perk. The cooldown time of the perks has decreased. Perks became more dangerous, and they could be used more often. And that’s when we saw the higher spike — version 1102.

Relation of RR1 and amount of times perks were used in 4 versions of the game (933, 1090, 1102, 1106).

Step #4. Finally, we went back to working on the user interface and added a "revenge screen" in the lower-left corner. The purpose of the screen is to kind of toy with players’ emotions. First, the trapped player received a custom animation of a specific character who threw a perk, making fun out of them. Secondly, the loser could now not only see who perk’ed them but also see all the bonuses (precious donuts!) they got for doing that. It set the mood and was very much in the style of our universe! But still, the growth in the number of perks used was modest compared to the previous version. Look at the chart above — 1106.

A logical conclusion came from this: interface, art and narrative solutions are important but secondary. The main tool for communicating with the player is the actual gameplay. And the best way to learn game mechanics is to play the game itself.

We’ll continue to experiment and develop the nonlinear PvP model for Donut Punks, and you can already try it for yourself with the beta version of the game available on Android.