diff --git a/Makefile b/Makefile
index 3ff039e4..631444f3 100644
--- a/Makefile
+++ b/Makefile
@@ -496,13 +496,20 @@ ballisticacore-windows/Generic/BallisticaCore.ico: .efrocachemap
 	@tools/pcommand efrocache_get $@
 
 ballisticacore-windows/build/Debug_%/BallisticaCoreGenericInternal.exe: \
-  ballisticacore-windows/build/Debug_%/BallisticaCoreGenericInternal.lib \
-  ballisticacore-windows/build/Debug_%/BallisticaCoreGenericInternal.pdb \
-  ballisticacore-windows/Generic/BallisticaCore.ico \
-  prereqs code resources
+   ballisticacore-windows/build/Debug_%/BallisticaCoreGenericInternal.lib \
+   ballisticacore-windows/build/Debug_%/BallisticaCoreGenericInternal.pdb \
+   ballisticacore-windows/Generic/BallisticaCore.ico \
+   prereqs code resources
 	WINDOWS_PROJECT=Generic WINDOWS_CONFIGURATION=Debug WINDOWS_PLATFORM=$* \
       ${MAKE} _windows-wsl-build
 
+# These are 'intermediate' files and will get deleted implicitly by make
+# if we don't do this.
+# See: https://www.gnu.org/software/make/manual/make.html#Special-Targets
+.PRECIOUS: \
+   ballisticacore-windows/build/Debug_%/BallisticaCoreGenericInternal.lib \
+   ballisticacore-windows/build/Debug_%/BallisticaCoreGenericInternal.pdb
+
 # Tell make which of these targets don't represent files.
 .PHONY: prefab-debug prefab-release prefab-debug-build prefab-release-build \
  prefab-server-debug prefab-server-release prefab-server-debug-build \
diff --git a/tools/batools/build.py b/tools/batools/build.py
index 3d784dd0..435c9946 100644
--- a/tools/batools/build.py
+++ b/tools/batools/build.py
@@ -76,9 +76,9 @@ class SourceCategory(Enum):
 
 class PrefabTarget(Enum):
     """Types of prefab builds able to be run."""
-    DEBUG = 'gui-debug'
+    GUI_DEBUG = 'gui-debug'
     SERVER_DEBUG = 'server-debug'
-    RELEASE = 'gui-release'
+    GUI_RELEASE = 'gui-release'
     SERVER_RELEASE = 'server-release'