There's a bug in the random level code.  One time that it checks

       rand() % MAXLEVEL

       it forgets to add one.  Here is a patch:


diff -ur gnome-games-1.1.90/gnibbles/main.c gnome-games-1.1.90-jjo/gnibbles/main.c
--- gnome-games-1.1.90/gnibbles/main.c  Tue Apr  3 13:54:25 2001
+++ gnome-games-1.1.90-jjo/gnibbles/main.c      Tue Apr  3 13:52:41 2001
@@ -488,7 +488,7 @@
               if ((current_level < MAXLEVEL) && !properties->random)
                       current_level++;
               else if (properties->random) {
-                       tmp = rand () % MAXLEVEL;
+                       tmp = rand () % MAXLEVEL + 1;
                       while (tmp == current_level)
                               tmp = rand () % MAXLEVEL + 1;
                       current_level = tmp;