• Why would our mercs travel so close to each other? This isn't a japanese subway.
• As they all look in one direction, it is very likely the enemy gets the first turn...
• ... and as they are all grouped so close together, a single grenade can effectively be the death of the entire team. Yeah yeah, 'but it's a surprise attack' and everything, but let's be honest. There's no way to avoid that apart from tedious savescumming. At higher difficulty levels, this is practically unwinnable.
• The enemy does not spawn in any cohesive way - they are all placed as usual. Jeez. You almost think they didn't plan the ambush, as if this is just some small code bit to simulate 'ambush' without any effort on Sirtech's part
• Why would the enemy spawn right next to our mercs, at point blank range? How did he come so close?

; If set to TRUE and mercs are ambushed, they won't start clustered in one location and looking in one direction.
; Instead they will be spread around the map central entry point, no more than AMBUSH_MERCS_SPREAD_RADIUS tiles away, and all looking outwards.
AMBUSH_MERCS_SPREAD = TRUE

AMBUSH_MERCS_SPREAD_RADIUS = 10

; If set to 1 and mercs are ambushed, enemies nearer than AMBUSH_MERCS_SPREAD_RADIUS to the map central entry point will instead be distributed more outward:
; They will be placed around that point, not closer than AMBUSH_ENEMY_ENCIRCLEMENT_RADIUS1 and not further away than AMBUSH_ENEMY_ENCIRCLEMENT_RADIUS2 tiles.
; They will face the center entry point (and thus the mercs).
; If set to 2, all enemies will be placed that way, not just those nearer than AMBUSH_MERCS_SPREAD_RADIUS.
AMBUSH_ENEMY_ENCIRCLEMENT = 1

AMBUSH_ENEMY_ENCIRCLEMENT_RADIUS1 = 15
AMBUSH_ENEMY_ENCIRCLEMENT_RADIUS2 = 30

As for the issue that came up on IRC last night (not sure if already solved or not):

The center entry point can be placed manually in the map editor, but it certainly should be locatable via its GridNo., no?

• The enemy encirclement radii are now dependent on your mercs' experience. The reasoning being that if your mercs are more experienced, they notice the enemy sooner, when he's further away... in pseudocode:
  

  radiusmodifier = ( 10 * (merc's experience level) + 50 * (merc is a scout) + (background ambush radius modifier) ) / 100
  

  This modifier is multiplied with AMBUSH_ENEMY_ENCIRCLEMENT_RADIUS1 and AMBUSH_ENEMY_ENCIRCLEMENT_RADIUS2. It is determined for each merc, the highest value counts.
• The radii values have also been increased in the ini. Still needs testing, perhaps even higher would be better, feedback welcome.
• A new background property (<ambush_radius>) is used in the above formula, values from 0 to 50. This effectively increases the range at which an enemy can appear in an ambush, and has been added to some backgrounds - mostly to special forces and mercs very experienced in ambushes.
• If your team has a member that is a very, very good leader, we presume they are quick-witted and determined enough to organize your team before combat - you can then deploy your mercs around the central entry point.
  
  The check needed to pass is
  

  leadership + 50 * (number of squadleader traits) > 120 (new trait system)
  respectively
  leadership + 30 > 120 (old trait system)
  

  It is determined for each merc, the highest value counts.
  As we can only draw rectangular overlays in this screen, some parts of that rectangle are inaccessible (as the allowed deployment zone is a circle), but that is a graphical 'bug' only.