-// number of rock image files.
-#define NROCKS 50
-// image file containing font for score stuff.
-#define BIG_FONT_FILE "fonts/score.png"
+#define XSCROLLTO (XSIZE/3)
+#define YSCROLLTO (YSIZE/2)
+
+#define BARRIER_SPEED 7.5
+
+#define MAX_DIST_AHEAD XSIZE
+#define BOUNCINESS 0.50
+
+
+// -----------------------------------------------------------------------
+// Rocks
+
+// number of rock images
+#define NROCKS 50
+
+// initial/final counts for rocks-on-screen
+#define NORMAL_I_ROCKS 20
+#define NORMAL_F_ROCKS 35 // after 2 minutes
+#define NORMAL_GAMESPEED 1.0