Forcefield 2

This is a new version of my Forcefield game. It now contains 26 working levels.

Changes since the last version:
- color-coded the force vectors
- improved the color scheme
- added portals
- tiles light up when hit, then stay dimly lit to show you which tiles actually affected the ball
- added moving obstacles
- added efficiency calculator (ratio of tiles actually hit to tiles moved, does not include blue tiles)
- improved graphics
- improved physics engine
- added anti-cheat mechanism

If the game lags, try turning lines off, setting the graphics quality to low, and disabling the "glow" effect.

Spoiler: Press "LEVEL" to go to the level select screen.