- start with something simple

- 2D

- scrolling background

- vector, images or both?  math / generated?  tiled?
  - background is images at the moment.
  - use images for characters / parts of characters too.  (just for a
    difference)  Can scale / rotate them if needed.

- hero?
  - start as a one-legged hopper ala Gish
    - triangular
      - need vectors, damn you modern X!

---------------------------------------- progress point ----------------------------------------

- hero?
  - person, animal, spaceship, platypus...?
    - progress to two legs, 4 legs (arms) etc ala Aquaria!

- animals
  - other people

- deep phyiscs
  - gravity
    - realistic 9.8 m/s/s.  Decide how big a metre is in the game.  Maybe 40 pixels / metre.
  - mass
  - position, velocity
  - gravity
  - rotational inertia
  - no tumbling for 2D thank goodness!

- scrolling
  - auto scroll ala Thrust
  - manual scroll
    - fix (don't scroll) button?

- problem solving with perhaps many solutions

- contact detection
  - normal reaction force
  - impact
  - how to do it?
    - peek pixels?
    - test bitmaps (masks) against one-another?
  - tile-based collision - work out what tiles an object is in, and check
    against those tiles background shapes, and other objects in those tiles
  - do I need to know what object it intersected?  yes!
  - do collision detection after updating position and velocity, and before
    plotting.  check:
    - 1. List objects by tile (1 or more tiles per object).  Include off-screen.
    - 2. Test bounding boxes
    - 3. For common scan-lines, test overlap.
    - 4. Calc actual collision points, time of impact, normal vector A->B.
    - 5. Calc impulse, angular impulse, and reacted position / velocity / spin
      for each object.

- name?

- platformer - but innovate
- ocean / water.  surface / underwater
- sloping or curved platforms
- acceleration, realistic feel - Exile; or more playable?
- digging
- bouncing rocks / balls
- puzzles?
- thaumaturgy, urging (like bending, ATLAB), elements, alchemy (FMA), magic, dying earth

- deep controls? - lean fwd/back.  left foot fwd / back  (or up fwd down!...), also arms, etc
  - learn to crawl or shuffle first.  can jump, etc...
    - maybe do this in the tutorial level.
  - macros: can program sequences of movements to fn keys or combos, etc., need to do this with repetition, like a learned habit / acquired reflex
  - do not 

- vision
  - can see only where you are looking, perhaps with shadowy outlines elsewhere of what you saw, that fade.  makes the rendering lighter too!

- hearing
  - stereo positioning for directional hearing


- unusual (for a game) bodily functions - sleep (drowsiness), tiredness / rest, elimination, hunger / thirst, bathing, sex, emotion (fear, ...), temperature
  - re: hunger, may need or want to cook.  Need fire for that... etc.

- terrain and vegetation based on cross-sections or 2D paths in the real world
  - probably don't include real-world cities / human buildings / streets, etc
    - include buildings / scenarios created for the game / by players in the game
  - default initial position could be based on your GPS or geo-ip location, with some randomisation

- weather based on real weather in that place (either now, or as recorded at some time)

- death is final, there are no 'lives'
  - game is 'saved' constantly and can be restored only once
  - this is enforced via the internet whenever possible - your game history must be unique
  - it is generally easy to avoid death
  - but, you can play again as a different character

- character creation
  - ala role playing?
  - choose physical attributes - height, etc.
    - smallness might be an advantage sometimes too

- network gaming / multi-player

- game security / copy protection
  - secret server component?
  - update component
  - competition for success
  - public domain (at least the libs, maybe whole game)
  - buy the game and service
  - pay what you feel, from the beginning

- collect gems
  - increases magic ability?
  - sell for tools / food / etc

- edit levels, by actually walking around in them and digging, etc?
  - use a different character for that, perhaps a demon

- include rotation, rotational inertia
- many more different animation frames for a character
  - crouch before jump
    - no special jump logic, it only happens according to normal collision
      reaction rules, with those crouch/jump animation frames