FLash Shooting game

Hi, this is my first game project, as you can see it’s inspired by Alien Hominid.
I’m not trying to rip it off, i just wanna know how to make it.

http://www.maive.co.uk/game.html

Basically the animation part is fine with me, but i keep having problems with coding it.

This is what i want it to do…

[SIZE=1]KEY>>[/SIZE][U]**[SIZE=1]ACTION

[/SIZE]**[/U][SIZE=1]NONE>> Stand still
Left >> Run left + scroll terrain right
Right>> Run right + scroll rerrain left
Down>> Dissappear and reappear further right
Left + Shift>> [/SIZE][SIZE=1]Run left + scroll terrain right + shoot left
[/SIZE][SIZE=1]Right + Shift>> [/SIZE][SIZE=1]Run Right + scroll terrain left + shoot right
[/SIZE][SIZE=1]Shift>> [/SIZE][SIZE=1]Shoot in the direction character is facing

[SIZE=2]I need a script for gravity, and collisions…
I want the character to be able to run into things like food etc to give more health.
It also needs to have a score board, score goes up with every enemy you shoot, and goes down everytime your shot.

If anyone knows of some usefull tutorials that would be great, as i would like to learn to code it my self.
Any help is greatly appreciated,
ZAXZA
[/SIZE][/SIZE]