diff --git a/engine/match.go b/engine/match.go
index ae0e3a3..0481992 100644
--- a/engine/match.go
+++ b/engine/match.go
@@ -364,7 +364,7 @@ func (mr *MatchRunner) generateMap(gs *GameState, numPlayers int) {
 
 	var primaryRadius, secondaryRadius float64
 	if numPlayers == 2 {
-		primaryRadius = 0.25   // ~10 tiles from center on 40x40 grid (~20 tiles apart, outside 5-tile attack radius)
+		primaryRadius = 0.125  // ~5 tiles from center on 40x40 grid (~10 tiles apart, within 5-tile attack radius)
 		secondaryRadius = 0.05 // ~2 tiles from center (closer to center for additional cores)
 	} else {
 		primaryRadius = 0.10 // ~5 tiles from center on 50x50 grid
diff --git a/engine/turn.go b/engine/turn.go
index ccc50fc..43fcc17 100644
--- a/engine/turn.go
+++ b/engine/turn.go
@@ -204,9 +204,9 @@ func (gs *GameState) updateZoneRadiusToContainBots() {
 	}
 
 	// Set zone radius to contain all bots plus margin
-	// Start with a larger margin to give bots time to move toward each other
+	// Margin is small to force bots together quickly before they can spread out
 	maxDist := int(sqrt(maxDist2))
-	gs.ZoneRadius = maxDist + 10 // Larger margin to give bots time to react
+	gs.ZoneRadius = maxDist + 5 // Smaller margin forces faster engagement
 }
 
 // sqrt returns the integer square root of n.
diff --git a/engine/types.go b/engine/types.go
index f5e33f6..1b6fb07 100644
--- a/engine/types.go
+++ b/engine/types.go
@@ -242,13 +242,13 @@ func ConfigForPlayers(numPlayers, coresPerPlayer int) Config {
 	if numPlayers == 2 {
 		cfg.ZoneStartTurn = 10     // Per plan §3.7.1 to force combat before bots can spread
 		cfg.ZoneShrinkInterval = 1 // Per plan §3.7.1
-		cfg.ZoneShrinkStep = 2     // Per plan §3.7.1: 2 tiles per step forces engagement
+		cfg.ZoneShrinkStep = 1     // Zone shrinks at same rate as bot movement (1 tile/turn)
 		cfg.ZoneMinRadius = 2      // Per plan §3.7.1: 2-player min radius
 		cfg.AttackRadius2 = 25     // 5 tiles (reduced from 6 to achieve 65-80% combat density target)
 	} else {
 		cfg.ZoneStartTurn = 10     // Per plan §3.7.1
 		cfg.ZoneShrinkInterval = 1 // Per plan §3.7.1
-		cfg.ZoneShrinkStep = 2     // Per plan §3.7.1: 2 tiles per step forces engagement
+		cfg.ZoneShrinkStep = 1     // Zone shrinks at same rate as bot movement (1 tile/turn)
 		cfg.ZoneMinRadius = 1      // Zone diameter (2) < attack radius (3.5), forces contact
 		cfg.AttackRadius2 = 12     // 3.5 tiles per plan §3.4 (3+ player)
 	}