diff --git a/.cargo/config.fast b/.cargo/config.fast
index 92730c0..aab734c 100644
--- a/.cargo/config.fast
+++ b/.cargo/config.fast
@@ -5,8 +5,10 @@
 linker = "/usr/bin/clang"
 rustflags = ["-Clink-arg=-fuse-ld=lld", "-Zshare-generics=y"]
 
+# NOTE: you must manually install https://github.com/michaeleisel/zld on mac. you can easily do this with the "brew" package manager:
+# `brew install michaeleisel/zld/zld`
 [target.x86_64-apple-darwin]
-rustflags = ["-Zshare-generics=y"]
+rustflags = ["-C", "link-arg=-fuse-ld=/usr/local/bin/zld", "-Zshare-generics=y"]
 
 [target.x86_64-pc-windows-msvc]
 linker = "rust-lld.exe"
diff --git a/setup b/setup
index 45965a1..7059042 100755
--- a/setup
+++ b/setup
@@ -2,7 +2,7 @@
 
 function ask_yn() {
   read -rp "❓ $1 (Y/n) " answer
-  if [[ "$answer" == "" || "$answer" == "y" || "$answer" == "Y" || "$answer" == "yes" || "$answer" == "Yes" ]] ; then
+  if [[ "$answer" == "" || "$answer" == "y" || "$answer" == "Y" || "$answer" == "yes" || "$answer" == "Yes" ]]; then
     return 0
   else
     return 1
@@ -17,28 +17,37 @@ function info() {
   echo "💡 $1"
 }
 
+function die() {
+  echo "🛑 FATAL: $1"
+}
+
+function warn() {
+  echo "⚠️ $1"
+}
+
 # --- Set package.name in Cargo.toml ---
 name_with_ext=$(git remote show -n origin | grep "Fetch URL" | cut -d / -f 2-)
 name="${name_with_ext%.*}"
-if grep -q "bevy_template" Cargo.toml ; then
-  if ask_yn "Set the package name to ${name}?" ; then
-    sed -e "s/bevy_template/${name}/" -i "" Cargo.toml \
-      && result "Set package name to ${name}"
+if grep -q "bevy_template" Cargo.toml; then
+  if ask_yn "Set the package name to ${name}?"; then
+    sed -e "s/bevy_template/${name}/" -i "" Cargo.toml || die "Couldn't set the package name to ${name}"
+    result "Set package name to ${name}"
   else
-    result "Okay, you should go set the package name in Cargo.toml manually."
+    warn "Okay, you should go set the package name in Cargo.toml manually."
   fi
 else
   info "Package name already set."
 fi
 
 # --- Set package.authors in Cargo.toml ---
-if grep -q "Unknown Author" Cargo.toml ; then
+if grep -q "Unknown Author" Cargo.toml; then
   DEFAULT_AUTHOR="$(git config --global user.name) <$(git config --global user.email)>"
-  if ask_yn "Set the author to ${DEFAULT_AUTHOR}?" ; then
-    sed -E -e "s/Unknown Author <unknown@example.com>/${DEFAULT_AUTHOR}/" -i "" Cargo.toml \
-      && result "Set author to ${DEFAULT_AUTHOR}"
+  if ask_yn "Set the author to ${DEFAULT_AUTHOR}?"; then
+    sed -E -e "s/Unknown Author <unknown@example.com>/${DEFAULT_AUTHOR}/" -i "" Cargo.toml ||
+      die "Couldn't set the author."
+    result "Set author to ${DEFAULT_AUTHOR}"
   else
-    result "Okay, you should go set the author in Cargo.toml manually."
+    warn "Okay, you should go set the author in Cargo.toml manually."
   fi
 else
   info "Author already set."
@@ -47,54 +56,67 @@ fi
 # --- Set latest version of Bevy ---
 json=$(curl --silent --user-agent "bevy_template (github.com/cleancut/bevy_template)" https://crates.io/api/v1/crates/bevy)
 version=$(echo "${json}" | grep -oE '"max_version":".*?"' | cut -d '"' -f 4)
-if ! grep -qE "^bevy = \"${version}\"\$" Cargo.toml ; then
-  if ask_yn "Try to update to the latest version of Bevy ($version)? If you have customized the version string, say no here." ; then
-    sed -E -e "s/^bevy = \".*\"\$/bevy = \"${version}\"/" -i "" Cargo.toml
-    result "Updated to version $version"
+if ! grep -qE "^bevy = \"${version}\"\$" Cargo.toml; then
+  if ask_yn "Try to update to the latest version of Bevy ($version)? If you have customized the version string, say no here."; then
+    sed -E -e "s/^bevy = \".*\"\$/bevy = \"${version}\"/" -i "" Cargo.toml || die "Couldn't update Bevy version to ${version}"
+    result "Updated to version ${version}"
   else
-    result "Okay, leaving the version alone."
+    warn "Okay, leaving the version alone."
   fi
 else
   info "Bevy is already on the latest version (${version}), skipping version update."
 fi
 
 # --- Configure fast-compile ---
-if [[ -f .cargo/config.fast ]] ; then
-  if ask_yn "Fast-compile is not configured. Would you like me to set it up now? If you don't want to use the nightly compiler, answer 'no'." ; then
-    mv .cargo/config.fast .cargo/config
-    result "Configured fast-compile."
-    if [[ $(uname) != "Darwin" ]] ; then
-      echo "⚠️ PLEASE INSTALL LLD!  Instructions are available at https://bevyengine.org/learn/book/getting-started/setup/"
-    fi
+if [[ -f .cargo/config.fast ]]; then
+  if ask_yn "Fast-compile is not configured. Would you like me to set it up now? This involves installing an external linker and using the nightly Rust compiler."; then
+    mv .cargo/config.fast .cargo/config || die "Failed moving config file into place"
+    result "Configured fast-compile to use zld/lld linker for debug builds."
   else
-    result "Okay, not configuring fast-compile."
+    warn "Okay, not configuring fast-compile."
   fi
-elif [[ -f .cargo/config ]] && grep -q -- "-Zshare-generics=y" .cargo/config ; then
+elif [[ -f .cargo/config ]] && grep -q -- "-Zshare-generics=y" .cargo/config; then
   info "Fast-compile is already configured. If you want to disable it, delete or comment out .cargo/config"
 fi
 
+if [[ $(uname) == "Darwin" ]]; then
+  if brew list michaeleisel/zld/zld > /dev/null 2> /dev/null ; then
+    info "zld is installed"
+  else
+    if ask_yn "Install zld? Answer yes if you configured fast-install." ; then
+      brew install michaeleisel/zld/zld \
+        || die "Failed running 'brew install michaeleisel/zld/zld -- do you have brew installed? https://brew.sh/"
+      result "installed zld"
+    else
+      warn "Okay, not installing zld."
+    fi
+  fi
+else
+  warn "PLEASE MAKE SURE YOU HAVE LLD INSTALLED!  Instructions are available at https://bevyengine.org/learn/book/getting-started/setup/"
+fi
+
 # --- Install nightly compiler ---
-if rustup toolchain list | grep -q nightly ; then
+if rustup toolchain list | grep -q nightly; then
   info "Nightly compiler already installed."
 else
-  if ask_yn "No nightly compiler installed. Install it via rustup? Answer 'yes' if you configured fast-compile." ; then
-    rustup install nightly
+  if ask_yn "No nightly compiler installed. Install it via rustup? Answer 'yes' if you configured fast-compile."; then
+    rustup install nightly || die "Failed to install nightly compiler. Do you have rustup installed?"
     result "Done installing nightly compiler."
   else
-    result "Okay, not installing nightly compiler."
+    warn "Okay, not installing nightly compiler."
   fi
 fi
 
 # --- Configure project to use nightly compiler ---
-if rustup toolchain list | grep -q nightly ; then
-  if rustup override list | grep -qE "$(pwd).*nightly" ; then
+if rustup toolchain list | grep -q nightly; then
+  if rustup override list | grep -qE "$(pwd).*nightly"; then
     info "Already using nightly compiler for this project."
   else
-    if ask_yn "Configure this project to use the nightly compiler? Answer 'yes' if you configured fast-compile." ; then
-      rustup override set nightly
+    if ask_yn "Configure this project to use the nightly compiler? Answer 'yes' if you configured fast-compile."; then
+      rustup override set nightly || die "Failed configuring project to use nightly compiler"
       result "Configured project to use the nightly compiler."
     else
-      result "Okay, not configuring project to use the nightly compiler."
+      warn "Okay, not configuring project to use the nightly compiler."
     fi
   fi
 else
@@ -102,24 +124,24 @@ else
 fi
 
 # --- Replace README.md ---
-if [[ -f README.md ]] && grep -q "Bevy Template" README.md ; then
-  if ask_yn "Replace template README.md with a blank one?" ; then
-    echo "# My Project" > README.md
+if [[ -f README.md ]] && grep -q "Bevy Template" README.md; then
+  if ask_yn "Replace template README.md with a blank one?"; then
+    echo "# My Project" > README.md || die "Failed replacing README.md"
     result "Replaced README.md with blank one."
   else
-    result "Okay, left template README.md in place."
+    warn "Okay, left template README.md in place."
   fi
 else
   info "README.md has already been replaced"
 fi
 
 # --- Delete the license ---
-if [[ -f LICENSE ]] && grep -q "Nathan Stocks" LICENSE ; then
-  if ask_yn "Delete the LICENSE file so you can add your own?" ; then
-    rm LICENSE
+if [[ -f LICENSE ]] && grep -q "Nathan Stocks" LICENSE; then
+  if ask_yn "Delete the LICENSE file so you can add your own?"; then
+    rm LICENSE || die "Failed deleting LICENSE file."
     result "Deleted the LICENSE file that belonged to the template. Feel free to license your project in whatever way you choose."
   else
-    result "Left LICENSE alone."
+    warn "Okay, left LICENSE alone."
   fi
 else
   info "Template license has already been removed."