diff --git a/engine/types.go b/engine/types.go
index e9feb48..ef7099b 100644
--- a/engine/types.go
+++ b/engine/types.go
@@ -242,13 +242,13 @@ func ConfigForPlayers(numPlayers, coresPerPlayer int) Config {
 	if numPlayers == 2 {
 		cfg.ZoneStartTurn = 20     // Start zone at turn 20 for 2-player (per plan §3.7.1)
 		cfg.ZoneShrinkInterval = 2 // Shrink every 2 turns per plan §3.7.1
-		cfg.ZoneShrinkStep = 1     // Shrink 2 tiles per interval (2 tiles/turn)
+		cfg.ZoneShrinkStep = 2     // 2 tiles per interval (per plan §3.7.1)
 		cfg.ZoneMinRadius = 3      // Final zone diameter (6) forces bots into attack range (3.5)
 		cfg.AttackRadius2 = 64     // 8 tiles for 2-player (plan default is 12; increased for combat density)
 	} else {
 		cfg.ZoneStartTurn = 15     // Start zone at turn 15 for 3+ players (per plan §3.7.1)
 		cfg.ZoneShrinkInterval = 2 // Shrink every 2 turns per plan §3.7.1
-		cfg.ZoneShrinkStep = 1     // Shrink 2 tiles per interval (1 tile/turn, per plan §3.7.1)
+		cfg.ZoneShrinkStep = 2     // 2 tiles per interval (per plan §3.7.1)
 		cfg.ZoneMinRadius = 3      // Final zone diameter (6) forces bots into attack range (3.5)
 		cfg.AttackRadius2 = 12     // 3.5 tiles per plan §3.4
 	}