Wednesday 16 January 2013

Let's Get Physical (on iPad!)

Back in Summer 2011 I was busy designing Greedy Bankers vs The World's multiplayer mode - an iPad-only variation where two players compete to make their fortune the fastest. I realised that rather than creating a separate game grid for each player, it would be easier just to build one giant grid with one side assigned to each player.

What came out of that turned out to be one of the most interesting and exciting parts of the game. Players weren't limited to using the gems on their grid. They could just reach over the board and steal anything they needed from their opponent! Players could get in each other's space, and that was great fun. To incentivise it, I added a bonus multiplier to every gem stolen, and the game took on a whole new lease of life.

Gems can be stolen in Greedy Bankers by taking them from your opponent's side

The game was for two players, but required both of them to use the whole screen as if it was their own. Players' approaches ranged from the desperately greedy to the polite and civilised, and some even descended into wrestling matches!

Noting that this was something very special, I wanted to explore this deeper in my next games. As such, it's why I ended up working on Slamjet Stadium - my upcoming multiplayer physics/sport mashup for iPad.

The tablet as a physical space

One of the great things about the tablet is it is a great big interactive canvas. You can do large gestural movements on it, you can play with objects without them being fiddly, and you can easily fit more than one hand on it at once. So it's the perfect device for physically-demanding touchscreen games, and there's plenty of room for multiplayer.

With two players sharing a physical space, the game world extends beyond the limits of the screen. It's no longer just what's on the display that players need to be aware of. They have to take notice of where their opponents' appendages are, in relation to what they're trying to get to. In Greedy Bankers vs The World, stealing a useful gem from right under your opponent's nose calls on this kind of awareness.

There's all kinds of exciting interactions that come out of physical play in games. JS Joust is a (deservedly) popular physical game that frequents games conferences, and soon PS3 thanks to its recent Kickstarter success. For the unfamiliar, in this game players hold a PS Move controller and must not let it move more than a certain amount. To win, players must cause their opponents to move, for example by pushing them or by causing them to dodge or trip. With the physical world so open to variation, players get to use their imagination to find ways to win.

In the tablet space, Michael Brough's O (video above) requires players to grab circles from the playfield, in a similar way to how gems are stolen in Greedy Bankers. However, as the scoring system rewards players to build chains of the same colour, opponents can be sabotaged by being given a circle that would break their chain. Fingle was an IGF finalist that used the multi-touch functionality of the iPad to get players to contort their fingers in various ways, so that players' hands were quite literally part of the game! Both of these require a lot of physical awareness of the other player, and have the player active on the whole of the board - a fresh type of challenge unique to tablet games.

The richness of physical interaction with touch screens and the infinite possibilities in player-to-player interaction makes physical games on iPad a joy to explore. This is why I was so excited to prototype around it, and these prototypes led me to my newest game, Slamjet Stadium.

A real social experience

One of the great things about these kinds of games is that they are so social, in a way that is so often lamented as shared-screen gaming gives way to online multiplayer. Testing for Greedy Bankers, Slamjet Stadium and the prototypes that came in-between commonly took place in the pub, and we'd always have plenty to talk about both during and after playing. They're something to gather around, something to laugh about. These games are perfect for parties, expos, and coffee tables. They generate stories to tell. Because both players are physically involved the experience is genuinely socially interactive, building friendships in a way that online social-network games cannot.

Two friends enjoying Slamjet Stadium at GameCity7

Another great aspect of these games is that players can decide their own rules. Much like board games and playground games, you can add your own variations. JS Joust can be played on your knees, for example. In Slamjet Stadium you can choose to grab an extra player and play two-against-one. The device is just the facilitator of the game, and it's up to players to referee it however they see fit.

In many ways, this is why I embraced the fact that the iPad cannot tell whose fingers are whose. Instead of forcing players to only interact with one side of the screen, Greedy Bankers effectively lets players pretend to be their opponent when stealing. That's what makes it feel so deliciously rebellious!

The iPad cannot identify players by which one is holding which game controller, so why separate players at all? All that the Greedy Bankers code needs to know is which player to award points to - it doesn't care how they were earned.

In Greedy Bankers vs The World, money is awarded to the player whose side the gem is on

Designing Slamjet Stadium as a physical multiplayer game

In Slamjet Stadium, players are not limited to certain sections of the screen - the characters act as their interactive tokens, and they can be manoeuvred to any position on the board. So players are allowed to make use of the whole play-space, but because there's many characters on screen at once there's no sense that you're wrestling over one part of the screen the whole time.

The four characters on the board offer four different ways of getting at the ball at any one time

Incidentally, this is one of the parts of Greedy Bankers that I wanted to improve on; because the centre of the screen was the node for all stealing, the stronger player pushing their opponent's hands away from that area often dominated play. Ideally, there should be some way around that, and having multiple characters in various positions in the arena alleviates this concern in Slamjet Stadium.

Players select different teams, each with their own unique traits, but they quickly notice that they can use any character they like on the board. I leave it to them to decide if they want to limit each player to only use their own team. Of course, adding this rule gives a new way to cheat if players can get away with it!

Dodging sawblades and laserbeams in Last Man Standing mode!

However, in certain stages of play it matters which team is your own, even if you're not controlling them. During "Last Man Standing" rounds, traps emerge and the winning player is the one whose characters survive. So even if you're using your opponent's characters, you need to make sure to throw them in the traps and protect your own! Having separate teams adds a challenge of awareness to play, rather than imposing a limitation on players.

The "Gust" powerup directs a powerful wind towards one of the goals

Similarly, the power-ups are activated by a pad in the centre of the screen, and choosing to activate it so that it affects you positively is a matter of timing. This shifts the focus of play and can benefit those paying attention to the arena as a whole. This is useful, as it prevents the game becoming a mash over one objective. A player who is in a tight spot can activate a power, if they're paying attention, to "flip" the game in their favour.

The balancing act

Of course, balancing all these factors to keep the game constantly flowing is a design challenge. As a designer you have to make sure that the variations are clear and obvious, without being confusing. This means continued player testing, and keeping an eye out for sticking points. Are players confused by any of the elements? Are there any dominant strategies? Is it a case of the most aggressive player winning? While I've been able to test it a lot throughout development, now is the time when all the functionality is in place, so I can really smooth out the experience as a whole.

Fortunately, in these physical games, the human layer means that over-powered strategies may not necessarily be a bad thing. If two players are fighting over the same objective, the human layer becomes the determining factor. Victory is determined by individuals' real-world strength, wits and guile. If a dominant strategy is only dominant part of the time, for example, then racing to to be the first to benefit is an exciting real-world challenge. The important thing is that play does not degenerate into a stalemate, and that's something I am glad to say does not seem to have happened, even from the earliest prototypes.

As a designer, this human layer is what makes these physical games so interesting. Rather than the flow of play being determined by the statistics inside the program, you really are leaving it up to the players to approach it in their own way. They can bend the rules. They can add to the experience by interacting beyond the screen, in that space of infinite possibilities that is the real world.

The players provide the fun, and the programmer is just the facilitator.

I think there's something very special about that.