+void play_music(const std::string& musicfile);
+
+/**
+ * Plays a soundfile
+ */
+void play_sound(const std::string& soundfile);
+
+/**
+ * Set the game_speed
+ */
+void set_game_speed(float speed);
+
+/**
+ * speeds Tux up
+ */
+void grease();
+
+/**
+ * makes Tux invincible for 10000 units of time
+ */
+void invincible();
+
+/**
+ * makes Tux a ghost, i.e. lets him float around and through solid objects
+ */
+void ghost();
+
+/**
+ * recall Tux's invincibility and ghost status
+ */
+void mortal();
+
+/**
+ * reinitialise and respawn Tux at the beginning of the current level
+ */
+void restart();
+
+/**
+ * print Tux's current coordinates in a level
+ */
+void whereami();
+
+/**
+ * move Tux near the end of the level
+ */
+void gotoend();
+
+/**
+ * show the camera's coordinates
+ */
+void camera();
+
+/**
+ * exit the game
+ */
+void quit();
+
+/**
+ * Returns a random integer
+ */
+int rand();