I really miss the percentage indicator from the fallot games when aiming at an enemy, is there any way to add this to the game?
Also, do all mercs have the same line of sight, or does it vary according to some stats? Also as far i as understad, the enemies see as far as you do, so how is it possible to see an enemy without him seeing you? Only if you go behind his back? I tried proning, crouching and standing while approaching an enemy and it seems he saw me at the same time, so i guess stance doesnt matter except for accuracy.

I don't know about the percentage, with the 1.13 mod you do see a red bar fill up to show how accurate a shot is but thats it. As for line of sight, sticking camo on a merc makes them harder to spot plus if they have the stealth ability it basically means you can snipe the enemy with impuntiy. The enemy have to get closer to your merc to spot them.

For example, if both you and your opponent are surrounded by nothing but darkness and you're the one using night vision goggles, you should be able to see him first.
Stance does affect visibility, but I think how big the advantage of crouching or lying prone is depends on the terrain. For example, crouching behind high grass or bushes should make you less visible than crouching in the middle of the street. This is what the manual says about your own light of sight:
"Holding down the END key will show you line of sight information for your selected
merc [...]
• Bright Green means you should be able to see an opponent in any stance at that
location.
• Yellow means there is one stance (out of three) in which an opponent would be
non-visible.
• Orange means there are two stances not visible at that location
• Red means that you shouldn’t be able to see the opponent regardless of his or
her stance."
If you press the END key while your merc is looking at a flat surface without any obstacles, you should get lots of green squares. If you press the END key while you're in the forest or a similarly cluttered area, there will be more orange squares where a crouching opponent would be invisible. While this is all about the line of sight of your own mercs, I think it applies to the opponents' sight as well.

Great thanks for the replies :) I did read this in the manual but i guess i thought the line of sight as being similar to the one in Commandos, where the cone being projected has different colors where you're not visible depending on where you are. I guess its different in JA, in that visibility depends on your cover and not on your distance.

In the 1.13 mod/patch (which I like now but it's hard as hell for new players) you get a bar that shows your chances of hitting. If you hit F in the original game you get Effective range of the gun you are using and the range to target you hit F on, in 1.13 you not only get that you also get the numbered percentage chance to hit the target. Really handy and main reason I used 1.13 from the beginning.