Gravitee Wars Post Mortem by Stuart Allen of FunkyPear


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Presentation by Stuart Allen of FunkyPear at Mochi London 2011, a post mortem of the highly successful game Gravitee Wars.

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Gravitee Wars Post Mortem by Stuart Allen of FunkyPear

  1. 1. Gravitee Wars A Post Mortem Speaker: Stuart Allen
  2. 2. Part 1: Background
  3. 3. The Gravitee Series●  Gravitee 1 and Gravitee 2 ●  Golf in space ●  Newtonian physics to simulate gravity ●  Sponsored by Kongregate
  4. 4. Gravitee 1●  Released September 2007●  Approximately 5m - 6m plays●  Current Ratings ●  Newgrounds – 4.22 (Front Page) ●  Kongregate – 4.00
  5. 5. Gravitee 2●  Released August 2009●  Approximately 4.5m - 5.5m plays●  Additional game modes & improved graphics●  Current Ratings ●  Newgrounds – 4.00 ●  Kongregate – 4.05 ●  Lower than Gravitee 1 – Original gameplay diluted?
  6. 6. Gravitee Wars●  Original concept for Gravitee 1●  Change of gameplay from golf to artillery ●  Concerned about alienating original players ●  Weapons and violence seem to do well!
  7. 7. Part 2: Development
  8. 8. Initial Thoughts●  Single player planned since day one●  Multiplayer possibilities for future games●  Unit personality●  Destructible planets●  AI quality important●  Cheap gameplay ●  Medals, achievements & rewards
  9. 9. Destructible Planets (1 of 3)●  Each planet originally a bitmap, with explosions being removed from the bitmap ●  Simple implementation ●  How to get units to walk around planets correctly? ●  How to calculate the new planets mass after an explosion?
  10. 10. Destructible Planets (2 of 3)●  Planet shape stored as a series of points ●  Planets made up of about 40 points●  Units walk around by following the line represented by two consecutive points●  Shape drawn to a Movieclip then used as a mask over the planet graphic●  Vector representation means mass easily calculated
  11. 11. Destructible Planets (3 of 3)●  When a planet is hit, another series of points representing explosions created●  Function takes the explosion and planet shapes and cuts the explosion shape out of the planet ●  Calculates intersections between the shapes ●  Walks around each shape until it intersects the other shape, then switch shape and continue until back to origin
  12. 12. Cheap Gameplay●  Wanted to use cheap gameplay to keep players playing ●  Better medals awarded for better scores ●  Achievements ●  Rewards –  New weapons –  Unit victory and idle animations –  Features (old school GFX, infinite ammo)
  13. 13. Unit Movement●  Units can walk around planet CW/CCW●  Started with Right = CW, Left = CCW ●  Makes less sense when at the bottom of a planet●  Decided to try to guess which way the player wanted to move ●  At top of planet R = CW, L = CCW ●  At bottom of planet L = CW, R = CCW
  14. 14. Artificial Intelligence (1 of 2)●  No experience with AI!●  Various stages ●  Are there any pickups I can get? ●  Am I directly in the line of sight of enemies? If so, is there somewhere I can retreat to after shooting that isnt? ●  Gravity set up too complicated to work out a power & angle to guarantee a hit.
  15. 15. Artificial Intelligence (2 of 2)●  AI throws out 720 different shots (72 different angles, 10 different powers)●  AI decides on which of those shots to take, based on who can be hit, how much health they have and what weapons are available●  Each enemy team has an accuracy score. Shots are knocked off by a random amount, based on this score.●  Originally if the AI couldnt hit an enemy it would move or teleport to another planet and try again
  16. 16. Part 3: Response
  17. 17. Response Overview●  Very well received!●  Hit the 1m gameplay mark after 6 days●  Total plays to date approx 12m – 15m●  Current Ratings ●  Newgrounds – 4.42 (Top 50 for a while) ●  Kongregate – 4.40 (Best of Nov 2010)
  18. 18. User Complaints (1 of 3)●  AI Flaws ●  Enemies take too long thinking – fixed ●  Enemies walk over mines ●  Enemies are too accurate with their shots ●  Enemies dont use all of the weapons
  19. 19. User Complaints (2 of 3)●  Balancing issues ●  Why dont the AI teams shoot at each other? ●  Money cheat – end score based on health remaining and damage done ●  After earning enough money, its easy to just meteor strike and nuke the enemy to death
  20. 20. User Complaints (3 of 3)●  Miscellaneous ●  Intuitive movement – hard to control ●  No multiplayer yet!
  21. 21. Revenue % Break Down
  22. 22. Thanks for listening! :)