-#define MAXROCKS 120 // MAX Rocks
-#define MAXROCKHEIGHT 100
-#define ROCKRATE 2
-#define MAXBLACKPOINTS 500
-#define MAXENGINEDOTS 5000
+#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
+
+#define EASY_I_ROCKS 10
+#define EASY_F_ROCKS 25 // after 2 minutes
+#define EASY_GAMESPEED 0.85
+
+// number of rock structs to allocate
+#define MAXROCKS 120
+
+#define THRUSTER_STRENGTH 1.5
+
+// how many engine dots come out of each thruster per tic (1/20th of a seccond)
+#define ENGINE_DOTS_PER_TIC 150
+
+#define MAXENGINEDOTS 10000