diff --git a/.editorconfig b/.editorconfig
index 537ddfac48..df5214ff8c 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -9,5 +9,5 @@ insert_final_newline = true
 [*.yaml]
 indent_size = 2
 
-[Makefile]
-indent_type = tab
+[{Makefile,*.mk}]
+indent_style = tab
diff --git a/Makefile b/Makefile
index ae7543bc27..ef5ff1efa1 100644
--- a/Makefile
+++ b/Makefile
@@ -1,135 +1,172 @@
-SHELL=/bin/bash -o pipefail
+### Build Options ###
 
-MAKEFLAGS += --no-builtin-rules
-MAKEFLAGS += --no-builtin-variables
+# Override these options in settings.mk or with `make SETTING=value'.
 
-################ Target Executable and Sources ###############
+BASEROM = baserom.z64
+TARGET = papermario
+COMPARE = 1
+NON_MATCHING = 0
 
-# BUILD_DIR is location where all build artifacts are placed
-BUILD_DIR = build
+-include settings.mk
 
-SRC_DIRS := $(shell find src -type d)
-ASM_DIRS := asm asm/os
-INCLUDE_DIRS := include include/PR src
-DATA_DIRS := $(shell mkdir -p bin && find bin -type d -not -name Yay0)
-YAY0_DIRS := bin/Yay0
-ASSETS_FS_DIRS := assets/fs
-ASSETS_FS_BIN := $(BUILD_DIR)/assets/fs.bin
-
-# Source code files
-C_FILES := $(foreach dir,$(SRC_DIRS),$(wildcard $(dir)/*.c))
-S_FILES := $(foreach dir,$(ASM_DIRS),$(wildcard $(dir)/*.s))
-ifdef PM_HEADER_REBUILD
-	H_FILES := $(foreach dir,$(INCLUDE_DIRS),$(wildcard $(dir)/*.h))
+# Fail early if baserom does not exist
+ifeq ($(wildcard $(BASEROM)),)
+$(error Baserom `$(BASEROM)' not found.)
 endif
-DATA_FILES := $(foreach dir,$(DATA_DIRS),$(wildcard $(dir)/*.bin))
-YAY0_FILES := $(foreach dir,$(YAY0_DIRS),$(wildcard $(dir)/*.bin))
-ASSETS_FS_FILES := $(foreach dir,$(ASSETS_FS_DIRS),$(wildcard $(dir)/*.*))
 
-# Object files
-ASSETS_FS_O := $(ASSETS_FS_BIN:.bin=.o)
-O_FILES := $(foreach file,$(C_FILES),$(BUILD_DIR)/$(file:.c=.c.o)) \
-		   $(foreach file,$(S_FILES),$(BUILD_DIR)/$(file:.s=.s.o)) \
-		   $(foreach file,$(DATA_FILES),$(BUILD_DIR)/$(file:.bin=.bin.o)) \
-		   $(ASSETS_FS_O) \
-		   $(foreach file,$(YAY0_FILES),$(BUILD_DIR)/$(file:.bin=.Yay0.o))
 
-####################### Tools #########################
+### Sources ###
 
-TOOLS = tools
-N64CKSUM = $(TOOLS)/n64crc
-SPLAT = ./$(TOOLS)/n64splat/split.py baserom.z64 $(TOOLS)/splat.yaml .
+include sources.mk
+
+
+### Output ###
+
+BUILD_DIR = build
+ROM = $(TARGET).z64
+ELF = $(BUILD_DIR)/$(TARGET).elf
+LD_SCRIPT = $(TARGET).ld
+LD_MAP = $(BUILD_DIR)/$(TARGET).map
+
+ifdef ASSETS_FS
+ASSETS_FS_OBJ = $(BUILD_DIR)/$(ASSETS_FS).o
+endif
+
+
+### Tools ###
+
+PYTHON = python3
+N64CKSUM = tools/n64crc
+SPLAT_YAML = tools/splat.yaml
+SPLAT = $(PYTHON) tools/n64splat/split.py $(BASEROM) $(SPLAT_YAML) .
+YAY0COMPRESS = tools/Yay0compress
+BUILD_ASSETS_FS := $(PYTHON) tools/build_assets_fs.py $(ASSETS_FS) $(BUILD_DIR)/$(ASSETS_FS)
+
+ifndef EMULATOR
+ifneq ($(shell command -v mupen64plus-gui),)
+EMULATOR = mupen64plus-gui
+else
+EMULATOR = mupen64plus
+endif
+endif
+
+
+### Compiler Options ###
 
-##################### Compiler Options #######################
 CROSS = mips-linux-gnu-
 AS = $(CROSS)as
-OLD_AS = $(TOOLS)/mips-nintendo-nu64-as
-CC = $(TOOLS)/cc1
+OLD_AS = tools/mips-nintendo-nu64-as
+CC = tools/cc1
+CPP = cpp
 LD = $(CROSS)ld
-OBJDUMP = $(CROSS)objdump
 OBJCOPY = $(CROSS)objcopy
 
-TARGET = papermario
-
 CPPFLAGS   = -Iinclude -Isrc -D _LANGUAGE_C -ffreestanding -DF3DEX_GBI_2
 ASFLAGS    = -EB -Iinclude -march=vr4300 -mtune=vr4300
 OLDASFLAGS = -EB -Iinclude -G 0
 CFLAGS     = -O2 -quiet -G 0 -mcpu=vr4300 -mfix4300 -mips3 -mgp32 -mfp32 -Wimplicit -Wuninitialized -Wshadow
-LDFLAGS    = -T undefined_syms.txt -T undefined_funcs.txt -T $(LD_SCRIPT) -Map $(BUILD_DIR)/papermario.map --no-check-sections
+LDFLAGS    = -T undefined_syms.txt -T undefined_funcs.txt -T $(LD_SCRIPT) -Map $(LD_MAP) --no-check-sections
 
-######################## Targets #############################
 
-default: all
-
-LD_SCRIPT = $(TARGET).ld
-
-all: $(TARGET).ld $(BUILD_DIR) $(TARGET).z64 verify
+### Targets ###
 
 clean:
-	rm -rf $(BUILD_DIR) $(TARGET).z64
-	make $(BUILD_DIR)
+	rm -rf $(BUILD_DIR)
 
-clean-code:
-	rm -rf $(BUILD_DIR)/src $(TARGET).z64
-	make $(BUILD_DIR)
+setup: clean submodules split
 
 submodules:
 	git submodule update --init --recursive
 
 split:
-	rm -rf bin && $(SPLAT) --modes ld bin Yay0 PaperMarioMapFS
+	rm -rf bin assets
+	$(SPLAT) --modes ld bin Yay0 PaperMarioMapFS
 
 split-all:
-	rm -rf $(DATA_DIRS) && $(SPLAT) --modes all
+	rm -rf bin assets
+	$(SPLAT) --modes all
 
-setup: clean submodules split
-	make -C $(TOOLS)
+test: $(ROM)
+ifdef EMULATOR
+	$(EMULATOR) $<
+else
+	@echo "N64 emulator not detected." && false
+endif
 
-print-% : ; $(info $* is a $(flavor $*) variable set to [$($*)]) @true
-
-$(BUILD_DIR):
-	mkdir -p $(BUILD_DIR)
-	@mkdir -p $(foreach dir,$(SRC_DIRS) $(ASM_DIRS) $(DATA_DIRS) $(ASSETS_FS_DIRS),build/$(dir))
-
-$(BUILD_DIR)/%.s.o: %.s
-	$(AS) $(ASFLAGS) -o $@ $<
-
-$(BUILD_DIR)/%.c.o: %.c $(H_FILES)
-	cpp $(CPPFLAGS) $< | $(CC) $(CFLAGS) -o - | $(OLD_AS) $(OLDASFLAGS) - -o $@
-
-$(BUILD_DIR)/%.bin.o: %.bin
-	$(LD) -r -b binary -o $@ $<
-
-$(BUILD_DIR)/assets/fs/%: assets/fs/%
-	@rm -f $@
-	$(TOOLS)/build_assets_fs.py $*
-
-$(BUILD_DIR)/assets/fs.bin: assets/fs.json $(TOOLS)/build_assets_fs.py $(foreach file,$(ASSETS_FS_FILES),build/$(file))
-	$(TOOLS)/build_assets_fs.py
-
-$(ASSETS_FS_O): $(ASSETS_FS_BIN)
-	$(LD) -r -b binary -o $@ $<
-
-$(BUILD_DIR)/%.Yay0.o: %.bin
-	mkdir -p build/bin/Yay0
-	$(TOOLS)/Yay0compress $< $<.Yay0
-	$(LD) -r -b binary -o $@ $<.Yay0
-
-$(LD_SCRIPT): $(TOOLS)/splat.yaml
+$(LD_SCRIPT): $(SPLAT_YAML)
 	$(SPLAT) --modes ld
 
-$(BUILD_DIR)/$(TARGET).elf: $(O_FILES) $(LD_SCRIPT)
-	$(LD) $(LDFLAGS) -o $@
+$(ROM): $(BUILD_DIR)/$(TARGET).bin
+	@cp $< $@
+ifeq ($(COMPARE),1)
+	@sha1sum -c checksum.sha1 || (echo 'The build succeeded, but did not match the base ROM. This is expected if you are making changes to the game. To skip this check, use "make COMPARE=0".' && false)
+endif
 
 $(BUILD_DIR)/$(TARGET).bin: $(BUILD_DIR)/$(TARGET).elf
 	$(OBJCOPY) $< $@ -O binary
 
-# final z64 updates checksum
-$(TARGET).z64: $(BUILD_DIR)/$(TARGET).bin
-	@cp $< $@
-	$(N64CKSUM) $@
+$(BUILD_DIR)/$(TARGET).elf: $(LD_SCRIPT) $(OBJECTS) $(ASSETS_FS_OBJ)
+	$(LD) $(LDFLAGS) -o $@
 
-verify: $(TARGET).z64
-	sha1sum -c checksum.sha1
+# `make print-VARNAME' to print the value of $(VARNAME)
+print-%: ; $(info $* is a $(flavor $*) variable set to [$($*)]) @true
 
-.PHONY: all clean default $(BUILD_DIR)
+
+### Object Targets (see sources.mk) ###
+
+ifndef OBJECTS
+$(warning OBJECTS is not defined by `sources.mk'.)
+else
+
+# C
+$(filter %.c.o,$(OBJECTS)): $(BUILD_DIR)/%.c.o: %.c
+	@mkdir -p $(shell dirname $@)
+	cpp $(CPPFLAGS) $< | $(CC) $(CFLAGS) -o - | $(OLD_AS) $(OLDASFLAGS) - -o $@
+
+# Assembly
+$(filter %.s.o,$(OBJECTS)): $(BUILD_DIR)/%.s.o: %.s
+	@mkdir -p $(shell dirname $@)
+	$(AS) $(ASFLAGS) -o $@ $<
+
+# Uncompressed data
+$(filter %.bin.o,$(OBJECTS)): $(BUILD_DIR)/%.bin.o: %.bin
+	@mkdir -p $(shell dirname $@)
+	$(LD) -r -b binary -o $@ $<
+
+# Compressed data
+$(filter %.Yay0.o,$(OBJECTS)): $(BUILD_DIR)/%.Yay0.o: %.bin
+	@mkdir -p $(shell dirname $@)
+	$(YAY0COMPRESS) $< $(BUILD_DIR)/$*.Yay0
+	$(LD) -r -b binary -o $@ $(BUILD_DIR)/$*.Yay0
+
+endif
+
+
+### Asset Filesystem (see sources.mk) ###
+
+# Complain if ASSETS_FS_SOURCES is undefined but ASSETS_FS is.
+ifndef ASSETS_FS_SOURCES
+ifdef ASSETS_FS
+$(warning ASSETS_FS_SOURCES is not defined by `sources.mk' but ASSETS_FS is.)
+endif
+else
+
+$(BUILD_DIR)/$(ASSETS_FS)/%: $(ASSETS_FS)/%
+	@mkdir -p $(shell dirname $@)
+	@rm -f $@
+	$(BUILD_ASSETS_FS) $*
+
+$(ASSETS_FS_OBJ): $(ASSETS_FS).json $(foreach file,$(ASSETS_FS_SOURCES),$(BUILD_DIR)/$(file))
+	$(BUILD_ASSETS_FS)
+	$(LD) -r -b binary -o $@ $(BUILD_DIR)/$(ASSETS_FS).bin
+
+endif
+
+
+### Make Settings ###
+
+.PHONY: clean test setup submodules split $(ROM)
+.DEFAULT_GOAL := $(ROM)
+
+# Remove built-in implicit rules to improve performance
+MAKEFLAGS += --no-builtin-rules
diff --git a/sources.mk b/sources.mk
new file mode 100644
index 0000000000..9706dbe917
--- /dev/null
+++ b/sources.mk
@@ -0,0 +1,35 @@
+### ASSETS_FS and ASSETS_FS_SOURCES ###
+
+# The asset filesystem path.
+ASSETS_FS = assets/fs
+
+# Source files to build the asset filesystem with. Each of these must be configured in `assets/fs.json'.
+ASSETS_FS_SOURCES = $(wildcard $(ASSETS_FS)/*.bin)
+
+
+### OBJECTS ###
+
+C_FILES = $(shell find src -type f -name "*.c" -not -name "*.inc.c")
+S_FILES = $(wildcard asm/*.s asm/os/*.s)
+
+BIN_FILES = $(foreach dir, $(shell mkdir -p bin && find bin -type d -not -name Yay0), $(wildcard $(dir)/*.bin))
+COMPRESSED_BIN_FILES = $(wildcard bin/Yay0/*.bin)
+
+# The OBJECTS variable holds the filenames of all object files to be linked.
+# Each of these objects should appear in `papermario.ld' (generated by n64splat).
+#
+# The extension of each object file specifies its source type (and, therefore, how it should be built):
+#
+#   Object ext | Source ext | Description
+#  ------------+------------+-------------
+#   .o         |            | Special; must have build steps declared here
+#   .c.o       | .c         | C sourcecode
+#   .s.o       | .s         | Assembly (built with modern assembler)
+#   .bin.o     | .bin       | Uncompressed data
+#   .Yay0.o    | .bin       | Compressed data
+#
+# Note that ASSETS_FS is linked implicitly and does not need to be listed here.
+
+OBJECTS = \
+	$(foreach file, $(C_FILES) $(S_FILES) $(BIN_FILES), $(BUILD_DIR)/$(file).o) \
+	$(foreach file, $(COMPRESSED_BIN_FILES), $(BUILD_DIR)/$(file:.bin=.Yay0.o))
diff --git a/tools/build_assets_fs.py b/tools/build_assets_fs.py
index 39a8e329f7..2830691963 100755
--- a/tools/build_assets_fs.py
+++ b/tools/build_assets_fs.py
@@ -39,7 +39,7 @@ def build_mapfs(src_dir, build_dir, out_bin):
             size = next_multiple(build_path.stat().st_size, 2)
             decompressed_size = src_path.stat().st_size
 
-            print(f"{name} {offset:08X} {size:08X} {decompressed_size:08X}")
+            #print(f"{name} {offset:08X} {size:08X} {decompressed_size:08X}")
 
             written_names.append(name)
             # write all previously-written names; required to match
@@ -93,9 +93,14 @@ def build_file(src_dir, out_dir, filename):
         shutil.copy(src_path, out_path)
 
 if __name__ == "__main__":
-    if len(sys.argv) > 1:
-        # copy (and compress if required) the given file
-        build_file("assets/fs", "build/assets/fs", sys.argv[1])
+    sys.argv.pop(0)
+    src = sys.argv.pop(0)
+    dest = sys.argv.pop(0)
+
+    if len(sys.argv) > 0:
+        # copy (and compress if required) the given file(s)
+        while len(sys.argv) > 0:
+            build_file(src, dest, sys.argv.pop())
     else:
         # build the aggregate file
-        build_mapfs("assets/fs", "build/assets/fs", "build/assets/fs.bin")
+        build_mapfs(src, dest, dest + ".bin")