diff --git a/.gitignore b/.gitignore
index ea8c4bf..ea74a56 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 /target
+/proprietary_roms
\ No newline at end of file
diff --git a/src/emulator.rs b/src/emulator.rs
index 7cabb03..949ebc4 100644
--- a/src/emulator.rs
+++ b/src/emulator.rs
@@ -142,7 +142,7 @@ where
             if self.delay_timer > 0 {
                 self.delay_timer -= 1
             }
-            if self.sound_timer > 0 {
+            if self.delay_timer > 0 {
                 self.delay_timer -= 1
             } else {
                 self.do_beep()
@@ -362,13 +362,13 @@ where
                 self.index_register = 0xF0 + (self.registers[vx as usize] & 0x0F) as u16;
             }
             ProcessorInstruction::BinaryCodedDecimalConversion(vx) => {
-                // todo!("must implement")
+                todo!("must implement")
             }
             ProcessorInstruction::LoadMemory(vx) => {
-                // todo!("must implement")
+                todo!("must implement")
             }
             ProcessorInstruction::StoreMemory(vx) => {
-                // todo!("must implement")
+                todo!("must implement")
             }
             _ => {
                 warn!("Unknown instruction: {:04x}, skipping.", instruction);