SMS Game Development

1
SMS Game Development

• Making the Most of a Sucky Technology

Greg Costikyan www.ungames.comwww.costik.comcost
ik_at_costik.com
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What Is SMS?

• Short Text Message Service

• Built into GSM from the startso everyone in
  Europe can text everyone else

• 20 b messages exchanged every month

• Not yet successful in North America carrier
  walled gardens breaking down but lower prices
  for voice pager/IM availability may continue to
  keep this smaller here

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Why Develop SMS Games?

• Everyone in Europe texts
• Comfortable with technology
• Perceived as cool (while WAP sucks)
• Potential large audience (and market)

• Carriers Aggregators eager for SMS titles
• In North America, too, where theyre waking up to
  the missed opportunity

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How Does it Work?

• Originator inputs phone number message.
• Sends message over air to SMSC.
• SMSC forwards message over Internet to
  recipients SMSC.
• SMSC sends message over air to recipient.

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SMSC Can Send Receive with Game Server

• Server is assigned a Phone Number

• User requests game by sending SMS to that number

• Header info identifies users phone number
  server parses, processes, responds to user.

• SMSC must know that phone number servers IP
  addressgame service must have a deal with the
  carrier!

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SMS Costs Money

• Typically 10/message (7p in UK)

• Carrier can choose to charge more or less for a
  games messages, or to charge a flat fee for a
  game.

• Revenues shared with game service

• Marketing cost in making users aware of phone
  number to message

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Game Should be Playable in Just a Few Message
Exchanges

• Otherwise will be too costly for many players

• Try to keep it to lt10 messages per game (or 1-3
  per day for games played over a period of time)

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Each Message Must Advance the Game

• In most games, the result of interaction can be
  minor (turn left 30 degrees a card is played).
  With SMS, a handful of interactions must combine
  to a satisfying game. A non-trivial design
  challenge.

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Each Message lt160 Characters

• Thats a hard limit.

• Can break into multiple messages, but each costs
  money

• Thats basically 25 words or less.

• Localizing generally increases the number of
  characters in text.

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Tricks to Help

• 2, not two.

• Abbrev. if can keep clear.

• Cn u use txting abbrevs?

• Edit ruthlessly.

• Put rules in separate Help message.

• Test all boundary conditions.

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No Graphics Means...

• Hard to show physical layout with pure text.
• Text adventures (N thru Door)but a lot of text
  used for navigation.
• Text representations (Ship 2 gt 3,7)but hard to
  visualize.

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Cant Rely on a Monospace Font

• This looks like this

CNRQKRNCPPPPPPPP........................PPPPP
PPPCNRKQRNC
CNRQKRNCPPPPPPPP........................PPPPP
PPPCNRKQRNC
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Avoid Games that Depend on Locations

• Most electronic games are an exploration of space

• But its not true of all game styles

• Word Games

• Choose a Maneuver Fighting games

• Tamagotchi

• Hammurabi

• conquest

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A Players Orders Are Text

• A command-line environment.

• Syntax Must be Transparent

• Syntax Must be Forgiving

• Demand the least text entry possible.

• Allow stackableorders.

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Latency is Off the Scale

• Typically, a minute or more.

• Interaction at discrete, separated moments.

• Each message really must count

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Dealing with Latency

• Turn-based games.
• Round-robin
• Simultaneous movement

• Act whenever games.
• Limited by real time

• Slow update games.

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Multiplayer or Die

• Head-to-Head games

• Limited-interaction large-scale multiplayer games

• Handful of players

• In-game messaging

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Smart Messaging

• Message concatenation (459 characters)

• BW bitmapped images (72x28)

• Ring tones (single voice)

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EMS Enhanced Message Service

• Message concatenation (3-6 messages)

• BW images, max 1k (32x32)

• Flip animations (32x32, 4-frame)

• Ringtones sounds

• 10 pre-installed sounds

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MMS Multimedia Message Service

• GIF89a animations, PNGs, JPEGs
• 640x480 in theory, in practice 174x133

• Sound AMR, WAV

• No limit to message length

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Punisher The Mobile Game
www.punisherthemobilegame.com www.riot-e.com
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Botfighters
www.botfighters.com www.itsalive.com
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Fisu
www.fisupeli.com www.smallplanet.fi
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Mobile Rome





www.gripstudios.com


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Doing Better

• Messaging Challenges

• Persistence

• Algorithmic, not Instantial

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URLs

• Nokia information emulator for MMS
  http//www.forum.nokia.com/main/1,35452,1_2_7,00.h
  tml (requires free registration)

• Ericsson info emulator for MMShttp//www.eric
  sson.com/mobilityworld/sub/open/technologies/messa
  ging/index.html?PUmessaging (requires free
  registration)