diff --git a/src/colour.rs b/src/colour.rs
index 2bc716a..ae34a97 100644
--- a/src/colour.rs
+++ b/src/colour.rs
@@ -6,6 +6,7 @@ pub struct Colour {
 }
 
 impl From<String> for Colour {
+    #[inline]
     fn from(string: String) -> Colour {
         let values: Vec<&str> = string.split(',').collect();
 
diff --git a/src/dialogue.rs b/src/dialogue.rs
index 9a5cfef..ad282ac 100644
--- a/src/dialogue.rs
+++ b/src/dialogue.rs
@@ -5,6 +5,7 @@ pub struct Dialogue {
 }
 
 impl From<String> for Dialogue {
+    #[inline]
     fn from(string: String) -> Dialogue {
         let lines: Vec<&str> = string.lines().collect();
         let id = lines[0].replace("DLG ", "").to_string();
diff --git a/src/ending.rs b/src/ending.rs
index 9ef6389..1969fec 100644
--- a/src/ending.rs
+++ b/src/ending.rs
@@ -6,6 +6,7 @@ pub struct Ending {
 }
 
 impl From<String> for Ending {
+    #[inline]
     fn from(string: String) -> Ending {
         let lines: Vec<&str> = string.lines().collect();
         let id = lines[0].replace("END ", "").to_string();
diff --git a/src/exit.rs b/src/exit.rs
index 2d59bae..4c9f2ac 100644
--- a/src/exit.rs
+++ b/src/exit.rs
@@ -14,6 +14,7 @@ pub enum Transition {
 }
 
 impl From<&str> for Transition {
+    #[inline]
     fn from(str: &str) -> Transition {
         match str {
             "fade_w" => Transition::FadeToWhite,
@@ -30,6 +31,7 @@ impl From<&str> for Transition {
 }
 
 impl ToString for Transition {
+    #[inline]
     fn to_string(&self) -> String {
         match &self {
             Transition::FadeToWhite => " FX fade_w",
@@ -56,6 +58,7 @@ pub struct Exit {
 }
 
 impl From<String> for Exit {
+    #[inline]
     fn from(string: String) -> Exit {
         // e.g. "EXT 6,4 0 10,12 FX fade_w"
         let room_position_effect: Vec<&str> = string.split_whitespace().collect();
@@ -77,6 +80,7 @@ impl From<String> for Exit {
 }
 
 impl ToString for Exit {
+    #[inline]
     fn to_string(&self) -> String {
         format!(
             "{} {}{}",
diff --git a/src/game.rs b/src/game.rs
index 6878c15..7e43c19 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -274,6 +274,7 @@ impl ToString for Game {
 }
 
 impl Game {
+    #[inline]
     pub fn tile_ids(&self) -> Vec<u64> {
         self.tiles.iter().map(|tile| tile.id).collect()
     }
@@ -281,6 +282,7 @@ impl Game {
     /// first available tile ID.
     /// e.g. if current tile IDs are [0, 2, 3] the result will be `1`
     ///      if current tile IDs are [0, 1, 2] the result will be `3`
+    #[inline]
     pub fn new_tile_id(&self) -> u64 {
         let mut new_id = 0;
 
@@ -299,6 +301,7 @@ impl Game {
     }
 
     /// adds a tile safely and returns the new tile ID
+    #[inline]
     pub fn add_tile(&mut self, mut tile: Tile) -> u64 {
         let new_id = self.new_tile_id();
         tile.id = new_id;
@@ -306,6 +309,7 @@ impl Game {
         new_id
     }
 
+    #[inline]
     fn version_line(&self) -> String {
         if self.version.is_some() {
             format!(
@@ -317,6 +321,7 @@ impl Game {
         }
     }
 
+    #[inline]
     fn room_format_line(&self) -> String {
         if self.room_format.is_some() {
             format!("\n\n! ROOM_FORMAT {}", self.room_format.unwrap().to_string())
@@ -325,6 +330,7 @@ impl Game {
         }
     }
 
+    #[inline]
     fn font_line(&self) -> String {
         if self.font == Font::AsciiSmall {
             "".to_string()
@@ -337,6 +343,7 @@ impl Game {
         }
     }
 
+    #[inline]
     fn text_direction_line(&self) -> &str {
         if self.text_direction == TextDirection::RightToLeft {
             "\n\nTEXT_DIRECTION RTL"
@@ -346,11 +353,13 @@ impl Game {
     }
 
     /// older bitsy games do not specify a version, but we can infer 1.0
+    #[inline]
     pub fn version(&self) -> Version {
         self.version.unwrap_or(Version { major: 1, minor: 0 })
     }
 
     /// older bitsy games do not specify a room format, but we can infer 0
+    #[inline]
     pub fn room_format(&self) -> RoomFormat {
         self.room_format.unwrap_or(RoomFormat::Contiguous)
     }
diff --git a/src/item.rs b/src/item.rs
index a26d7e3..09578ff 100644
--- a/src/item.rs
+++ b/src/item.rs
@@ -10,20 +10,24 @@ pub struct Item {
 }
 
 impl Item {
+    #[inline]
     fn name_line(&self) -> String {
         optional_data_line("NAME", self.name.as_ref())
     }
 
+    #[inline]
     fn dialogue_line(&self) -> String {
         optional_data_line("DLG", self.dialogue_id.as_ref())
     }
 
+    #[inline]
     fn colour_line(&self) -> String {
         optional_data_line("COL", self.colour_id.as_ref())
     }
 }
 
 impl From<String> for Item {
+    #[inline]
     fn from(string: String) -> Item {
         let mut lines: Vec<&str> = string.lines().collect();
 
diff --git a/src/lib.rs b/src/lib.rs
index 533f421..72e16a5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -72,11 +72,13 @@ impl AnimationFrames for Vec<Image> {
     }
 }
 
+#[inline]
 fn from_base36(str: &str) -> u64 {
     u64::from_str_radix(str, 36).expect(&format!("Invalid base36 string: {}", str))
 }
 
 /// this doesn't work inside ToBase36 for some reason
+#[inline]
 fn to_base36(int: u64) -> String {
     format!("{}", radix_36(int))
 }
@@ -86,12 +88,14 @@ pub trait ToBase36 {
 }
 
 impl ToBase36 for u64 {
+    #[inline]
     fn to_base36(&self) -> String {
         to_base36(*self)
     }
 }
 
 /// e.g. `\nNAME DLG_0`
+#[inline]
 fn optional_data_line<T: Display>(label: &str, item: Option<T>) -> String {
     if item.is_some() {
         format!("\n{} {}", label, item.unwrap())
@@ -100,6 +104,7 @@ fn optional_data_line<T: Display>(label: &str, item: Option<T>) -> String {
     }
 }
 
+#[inline]
 fn transform_line_endings(input: String, mode: TransformMode) -> String {
     let mut input = Cursor::new(input);
     let mut output = Cursor::new(Vec::new());
@@ -108,6 +113,7 @@ fn transform_line_endings(input: String, mode: TransformMode) -> String {
     String::from_utf8(output.into_inner()).unwrap()
 }
 
+#[inline]
 fn segments_from_string(string: String) -> Vec<String> {
     let mut output:Vec<String> = Vec::new();
     // are we inside `"""\n...\n"""`? if so, ignore empty lines
@@ -133,8 +139,9 @@ fn segments_from_string(string: String) -> Vec<String> {
     output
 }
 
-// for some reason the sprites with numeric IDs go first,
-// then SPR A (avatar), then all the non-numeric IDs
+/// for some reason the sprites with numeric IDs go first,
+/// then SPR A (avatar), then all the non-numeric IDs
+#[inline]
 fn is_string_numeric(str: String) -> bool {
     for c in str.chars() {
         if !c.is_numeric() {
diff --git a/src/mock.rs b/src/mock.rs
index ae0b5a5..86f244c 100644
--- a/src/mock.rs
+++ b/src/mock.rs
@@ -4,6 +4,7 @@ use crate::game::{RoomType, RoomFormat};
 pub mod image {
     use crate::Image;
 
+    #[inline]
     pub(crate) fn chequers_1() -> Image {
         Image {
             pixels: vec![
@@ -14,6 +15,7 @@ pub mod image {
         }
     }
 
+    #[inline]
     pub fn chequers_2() -> Image {
         Image {
             pixels: vec![
@@ -25,6 +27,7 @@ pub mod image {
     }
 }
 
+#[inline]
 pub fn avatar() -> Sprite {
     Sprite {
         id: 0,
@@ -53,6 +56,7 @@ pub fn avatar() -> Sprite {
     }
 }
 
+#[inline]
 pub fn tile_default() -> Tile {
     Tile {
         id: 10,
@@ -69,6 +73,7 @@ pub fn tile_default() -> Tile {
     }
 }
 
+#[inline]
 pub fn sprite() -> Sprite {
     Sprite {
         id: 10,
@@ -88,6 +93,7 @@ pub fn sprite() -> Sprite {
     }
 }
 
+#[inline]
 pub fn item() -> Item {
     Item {
         id: 6,
@@ -104,6 +110,7 @@ pub fn item() -> Item {
     }
 }
 
+#[inline]
 pub fn room() -> Room {
     Room {
         id: 10,
@@ -407,6 +414,7 @@ pub fn room() -> Room {
     }
 }
 
+#[inline]
 pub fn game_default() -> Game {
     Game {
         name: "Write your game's title here".to_string(),
diff --git a/src/palette.rs b/src/palette.rs
index 58f3c35..eae6dc0 100644
--- a/src/palette.rs
+++ b/src/palette.rs
@@ -9,6 +9,7 @@ pub struct Palette {
 }
 
 impl From<String> for Palette {
+    #[inline]
     fn from(string: String) -> Palette {
         let lines: Vec<&str> = string.lines().collect();
 
diff --git a/src/position.rs b/src/position.rs
index c24e190..e31ddd5 100644
--- a/src/position.rs
+++ b/src/position.rs
@@ -7,6 +7,7 @@ pub struct Position {
 }
 
 impl Position {
+    #[inline]
     pub(crate) fn from(string: String) -> Result<Position, &'static dyn Error> {
         // e.g. "2,5"
         let xy: Vec<&str> = string.split(',').collect();
diff --git a/src/room.rs b/src/room.rs
index 892e947..cd4ee0e 100644
--- a/src/room.rs
+++ b/src/room.rs
@@ -15,10 +15,12 @@ pub struct Room {
 }
 
 impl Room {
+    #[inline]
     fn name_line(&self) -> String {
         optional_data_line("NAME", self.name.as_ref())
     }
 
+    #[inline]
     fn wall_line(&self) -> String {
         if self.walls.len() > 0 {
             let ids: Vec<String> = self.walls.iter().map(|&id| id.to_base36()).collect();
@@ -28,6 +30,7 @@ impl Room {
         }
     }
 
+    #[inline]
     fn palette_line(&self) -> String {
         if self.palette_id.is_some() {
             optional_data_line("PAL", Some(self.palette_id.unwrap().to_base36()))
@@ -38,6 +41,7 @@ impl Room {
 }
 
 impl From<String> for Room {
+    #[inline]
     fn from(string: String) -> Room {
         let string = string.replace("ROOM ", "");
         let string = string.replace("SET ", "");
@@ -141,6 +145,7 @@ impl From<String> for Room {
 }
 
 impl Room {
+    #[inline]
     pub fn to_string(&self, room_format: RoomFormat, room_type: RoomType) -> String {
         let mut tiles = String::new();
         let mut items = String::new();
diff --git a/src/sprite.rs b/src/sprite.rs
index 7660446..bdd4a74 100644
--- a/src/sprite.rs
+++ b/src/sprite.rs
@@ -13,14 +13,17 @@ pub struct Sprite {
 }
 
 impl Sprite {
+    #[inline]
     fn name_line(&self) -> String {
         optional_data_line("NAME", self.name.as_ref())
     }
 
+    #[inline]
     fn dialogue_line(&self) -> String {
         optional_data_line("DLG", self.dialogue_id.as_ref())
     }
 
+    #[inline]
     fn room_position_line(&self) -> String {
         if self.room_id.is_some() && self.position.is_some() {
             format!(
@@ -33,10 +36,12 @@ impl Sprite {
         }
     }
 
+    #[inline]
     fn colour_line(&self) -> String {
         optional_data_line("COL", self.colour_id.as_ref())
     }
 
+    #[inline]
     fn item_lines(&self) -> String {
         if self.items.len() == 0 {
             "".to_string()
@@ -48,6 +53,7 @@ impl Sprite {
 }
 
 impl From<String> for Sprite {
+    #[inline]
     fn from(string: String) -> Sprite {
         let mut lines: Vec<&str> = string.lines().collect();
 
diff --git a/src/text.rs b/src/text.rs
index 8755421..ee0c8f0 100644
--- a/src/text.rs
+++ b/src/text.rs
@@ -9,6 +9,7 @@ pub enum Font {
 }
 
 impl Font {
+    #[inline]
     pub(crate) fn from(str: &str) -> Font {
         match str {
             "unicode_european_small" => Font::UnicodeEuropeanSmall,
@@ -19,6 +20,7 @@ impl Font {
         }
     }
 
+    #[inline]
     pub(crate) fn to_string(&self) -> Result<String, &'static str> {
         match &self {
             Font::UnicodeEuropeanSmall => Ok("unicode_european_small".to_string()),
diff --git a/src/tile.rs b/src/tile.rs
index 0d1333c..060c903 100644
--- a/src/tile.rs
+++ b/src/tile.rs
@@ -10,10 +10,12 @@ pub struct Tile {
 }
 
 impl Tile {
+    #[inline]
     fn name_line(&self) -> String {
         optional_data_line("NAME", self.name.as_ref())
     }
 
+    #[inline]
     fn wall_line(&self) -> String {
         if self.wall.is_some() {
             format!("\nWAL {}", self.wall.unwrap())
@@ -22,6 +24,7 @@ impl Tile {
         }
     }
 
+    #[inline]
     fn colour_line(&self) -> String {
         if self.colour_id.is_some() {
             format!("\nCOL {}", self.colour_id.unwrap())
diff --git a/src/variable.rs b/src/variable.rs
index 2473bf4..8f225ed 100644
--- a/src/variable.rs
+++ b/src/variable.rs
@@ -5,6 +5,7 @@ pub struct Variable {
 }
 
 impl From<String> for Variable {
+    #[inline]
     fn from(string: String) -> Variable {
         let id_value: Vec<&str> = string.lines().collect();
         let id = id_value[0].replace("VAR ", "").to_string();