diff --git a/Makefile b/Makefile
index b71aece..9e9e7a9 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 CXXFLAGS ?= -O2 -Wall -g
 CXXFLAGS += `pkg-config --cflags sdl2 SDL2_image SDL2_mixer` -DLINUX
 LIBS = `pkg-config --libs sdl2 SDL2_image SDL2_mixer`
-OBJS = aliens.o audio.o bullets.o cargo.o collectable.o comms.o debris.o events.o explosions.o game.o globals.o graphics.o init.o intermission.o loadSave.o messages.o misc.o missions.o player.o resources.o script.o shop.o Starfighter.o title.o weapons.o
+OBJS = alien.o audio.o bullets.o cargo.o collectable.o comms.o debris.o events.o explosions.o game.o globals.o graphics.o init.o intermission.o loadSave.o messages.o misc.o missions.o player.o resources.o script.o shop.o Starfighter.o title.o weapons.o
 
 VERSION = 1.3-dev
 PROG = starfighter
diff --git a/src/Starfighter.h b/src/Starfighter.h
index c2bc7fa..f074026 100644
--- a/src/Starfighter.h
+++ b/src/Starfighter.h
@@ -35,7 +35,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "defs.h"
 #include "structs.h"
 
-#include "aliens.h"
+#include "alien.h"
 #include "audio.h"
 #include "bullets.h"
 #include "cargo.h"
diff --git a/src/aliens.cpp b/src/alien.cpp
similarity index 100%
rename from src/aliens.cpp
rename to src/alien.cpp
diff --git a/src/aliens.h b/src/alien.h
similarity index 100%
rename from src/aliens.h
rename to src/alien.h
diff --git a/src/bullets.h b/src/bullets.h
index 82e1162..b808b0b 100644
--- a/src/bullets.h
+++ b/src/bullets.h
@@ -17,8 +17,8 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef _BULLETS_H_
-#define _BULLETS_H_
+#ifndef BULLETS_H
+#define BULLETS_H
 
 extern void addBullet(object *theWeapon, object *attacker, int y, int dy);
 extern void fireBullet(object *attacker, int weaponType);