diff --git a/src/bus.rs b/src/bus.rs
index 2400cfa..c8bea42 100644
--- a/src/bus.rs
+++ b/src/bus.rs
@@ -5,7 +5,7 @@
 //!
 //! This is more of a memory management unit + some utils for reading/writing
 
-use crate::error::Result;
+use crate::error::{Error::MissingRegion, Result};
 use std::{
     fmt::{Debug, Display, Formatter},
     ops::Range,
@@ -319,9 +319,7 @@ impl Bus {
                 }
             }
         } else {
-            return Err(crate::error::Error::MissingRegion {
-                region: REGION.to_string(),
-            });
+            return Err(MissingRegion { region: REGION });
         }
         Ok(())
     }
diff --git a/src/error.rs b/src/error.rs
index bf0b197..c526107 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -3,6 +3,7 @@
 
 //! Error type for Chirp
 
+use crate::bus::Region;
 use thiserror::Error;
 
 pub type Result<T> = std::result::Result<T, Error>;
@@ -10,13 +11,15 @@ pub type Result<T> = std::result::Result<T, Error>;
 #[derive(Debug, Error)]
 pub enum Error {
     #[error("Unrecognized opcode {word}")]
-    UnimplementedInstruction { word: u16 },
-    #[error("Math was funky when parsing {word}: {explanation}")]
-    FunkyMath { word: u16, explanation: String },
+    UnimplementedInstruction {
+        word: u16,
+    },
     #[error("No {region} found on bus")]
-    MissingRegion { region: String },
+    MissingRegion {
+        region: Region,
+    },
     #[error(transparent)]
     IoError(#[from] std::io::Error),
     #[error(transparent)]
-    WindowError(#[from] minifb::Error),
+    MinifbError(#[from] minifb::Error),
 }
diff --git a/tests/integration.rs b/tests/integration.rs
index 2d7a6e0..6eff219 100644
--- a/tests/integration.rs
+++ b/tests/integration.rs
@@ -191,10 +191,8 @@ mod cpu {
 
 #[test]
 fn error() {
-    let error = chirp::error::Error::FunkyMath {
-        word: 0x1234,
-        explanation: "This shit was funky".to_owned(),
-    };
+    let error = chirp::error::Error::MissingRegion { region: Screen };
+    // Print it with Display and Debug
     println!("{error} {error:?}");
 }