Here is some basics about how the game work, how to make points and how the score's system works.

Section: 1st ) Carson city : 2 levels + 1 Boss 2nd) Desolation Canyon : 2 levels + 1 Boss 3rd) Ammunition Depot : 2 levels + 1 Boss 4th) Gold Mine : 2 levels + 1 Boss 5th) Train: 2 levels + 2 Boss 6th) Kid's lair: 3 levels + The Boss

Notice that you can choose the order between the 2nd and the 5th.

Scoring:

Items:	- Gold Bag : 		500pts
		- Brown nugget : 	1000 pts
		- Blue nugget:		1500pts
		- Red nugget		5000pts

Combo:	If you kill several enemies in a row, you multiply your score (the score from this kill) by 2, than 3
		untill a maximum of 5x. BUT you have not to move, never stop shooting, never using the rope.
		The combo is the key to make a huge score !

Stage:	Every single part of the set that you can destroyed gives between 10 to 100 pts

Enemies:	Some enemies worth 100pts some more. The mini boss worth usually 1k to 1.5k.

Time:	Most enemies decrease the second remaining when they are killed.

Bonus stage:	There are two bonus games during the entire game. They take place after the second and after the  
			fourth section.

End of section:	After each section, the game gives you some extra points:

			- Bonus from the stage
			- Items you've collected x 500

Death:		When you die the game doesn't withdraw any points from your score. BUT at the end of the section
			you loose all the items you had collected before your death !

Extra life:		- Every 100 000pts you get an extra life
			- The screen cannot displayed more than 9 lifes. BUT there are counted anyway.
			- At the end of the last section, every extra life will be added for 100 000pts each.

Bonus Rank:	At the end of the game (last section), the game add a bonus to your score. Depending of the game level:	
	- Easy mode: 500'000pts
	- Normal mode: 700'000pts
	- Hard mode: 1'000'000pts

This is from my knowledge of the game. It is not exhaustive. And if someone discover some others things. He is welcome to add his knowledge.

timxtim