diff --git a/src/inventory.rs b/src/inventory.rs
index 0cab938..7607676 100644
--- a/src/inventory.rs
+++ b/src/inventory.rs
@@ -73,6 +73,22 @@ impl Inventory {
         self.weapons.get_mut(self.current_weapon as usize)
     }
 
+    pub fn next_weapon(&mut self) {
+        if (1 + self.current_weapon as usize) < self.weapons.len() {
+            self.current_weapon += 1;
+        } else {
+            self.current_weapon = 0;
+        }
+    }
+
+    pub fn prev_weapon(&mut self) {
+        if self.current_weapon as usize > 0 {
+            self.current_weapon -= 1;
+        } else {
+            self.current_weapon = self.weapons.len().saturating_sub(1) as u16;
+        }
+    }
+
     pub fn refill_all_ammo(&mut self) {
         for weapon in self.weapons.iter_mut() {
             weapon.ammo = weapon.max_ammo;
diff --git a/src/scene/game_scene.rs b/src/scene/game_scene.rs
index bd68a89..2e88dfe 100644
--- a/src/scene/game_scene.rs
+++ b/src/scene/game_scene.rs
@@ -151,11 +151,11 @@ impl GameScene {
 
         let weapon_count = self.inventory.get_weapon_count();
         if weapon_count != 0 {
-            let current_weapon = self.inventory.get_current_weapon_idx() as usize;
+            let current_weapon = self.inventory.get_current_weapon_idx() as isize;
             let mut rect = Rect::new(0, 0, 0, 16);
 
             for a in 0..weapon_count {
-                let mut pos_x = ((a - current_weapon) as f32 * 16.0) + weap_x;
+                let mut pos_x = ((a as isize - current_weapon) as f32 * 16.0) + weap_x;
 
                 if pos_x < 8.0 {
                     pos_x += 48.0 + weapon_count as f32 * 16.0;
@@ -753,6 +753,16 @@ impl Scene for GameScene {
                 weapon.shoot_bullet(&self.player, &mut self.bullet_manager, state);
             }
 
+            if state.key_trigger.weapon_next() {
+                self.inventory.next_weapon();
+                self.weapon_x_pos = 32;
+            }
+
+            if state.key_trigger.weapon_prev() {
+                self.inventory.prev_weapon();
+                self.weapon_x_pos = 0;
+            }
+
             // update health bar
             if self.life_bar < self.player.life as u16 {
                 self.life_bar = self.player.life as u16;