x - done
p - partially

[x]	- game objects IDs and icons
[p]	- Reading levels from file (needs better error detecting)
[x]	- Teleportation
[x]     - Moving algorithms for birds
[x]     - Moving algorithms for bears (Thanks to Zbigniew Chyla)
[x]	- Moving butterflies
[x]	- Questionmark implementing (needs really random objects generation)
[x]	- Solid laser
[x]     - Rotating guns
[x]     - Moving guns
[p]	- Start sequence (needs some moving, help, polishing etc..)
[x]     - Gun shooting
[p]	- Better scrolling (now is SCROLL_RATE jumping - not working perfect) 
[p]     - Delay parameters fitting
[p]     - Fine level changing with scrolling effect
[x]     - Merging all little icons into big one 
[ ]     - Sound and sound effects
[p]     - Too much structures (remove something...)
[x]	- Blasters
[x]     - Shooting birds
[x]     - Magnets' behaviour
[ ]     - Port all available levels from Atari
[x]     - Score more similar to original game
[p]     - Better graphics (and bigger)... (bigger as for now completed)
[x]     - GameSaving or codes for planets
[p]     - End screen (after completing the game)
[ ]     - XML format for levels (and maybe separate files would be better)
[ ]     - Creator for manually edit and testing the planets by user
[ ]     - Adding the joystick
[ ]     - Reimplementing some functions for making them better and faster
[x]	- Remember last done level in .gnurobborc file in user home dir
[x]	- Energetic barrier