diff --git a/source/funkin/data/DataParse.hx b/source/funkin/data/DataParse.hx
index cbd168a61..49dde0198 100644
--- a/source/funkin/data/DataParse.hx
+++ b/source/funkin/data/DataParse.hx
@@ -178,7 +178,31 @@ class DataParse
     switch (json.value)
     {
       case JObject(fields):
-        return cast Tools.getValue(json);
+        var result:LegacyNoteSection =
+          {
+            mustHitSection: false,
+            sectionNotes: [],
+          };
+        for (field in fields)
+        {
+          switch (field.name)
+          {
+            case 'sectionNotes':
+              result.sectionNotes = legacyNotes(field.value, field.name);
+
+            case 'mustHitSection':
+              result.mustHitSection = Tools.getValue(field.value);
+            case 'typeOfSection':
+              result.typeOfSection = Tools.getValue(field.value);
+            case 'lengthInSteps':
+              result.lengthInSteps = Tools.getValue(field.value);
+            case 'changeBPM':
+              result.changeBPM = Tools.getValue(field.value);
+            case 'bpm':
+              result.bpm = Tools.getValue(field.value);
+          }
+        }
+        return result;
       default:
         throw 'Expected property $name to be an object, but it was ${json.value}.';
     }
@@ -189,7 +213,12 @@ class DataParse
     switch (json.value)
     {
       case JObject(fields):
-        return cast Tools.getValue(json);
+        var result = {};
+        for (field in fields)
+        {
+          Reflect.setField(result, field.name, legacyNoteSectionArray(field.value, field.name));
+        }
+        return result;
       default:
         throw 'Expected property $name to be an object, but it was ${json.value}.';
     }
@@ -211,13 +240,13 @@ class DataParse
     switch (json.value)
     {
       case JArray(values):
-        // var time:Null<Float> = values[0] == null ? null : Tools.getValue(values[0]);
-        // var data:Null<Int> = values[1] == null ? null : Tools.getValue(values[1]);
-        // var length:Null<Float> = values[2] == null ? null : Tools.getValue(values[2]);
-        // var alt:Null<Bool> = values[3] == null ? null : Tools.getValue(values[3]);
+        var time:Null<Float> = values[0] == null ? null : Tools.getValue(values[0]);
+        var data:Null<Int> = values[1] == null ? null : Tools.getValue(values[1]);
+        var length:Null<Float> = values[2] == null ? null : Tools.getValue(values[2]);
+        var alt:Null<Bool> = values[3] == null ? null : Tools.getValue(values[3]);
 
-        // return new LegacyNote(time, data, length, alt);
-        return null;
+        return new LegacyNote(time, data, length, alt);
+      // return null;
       default:
         throw 'Expected property $name to be a note, but it was ${json.value}.';
     }
diff --git a/source/funkin/data/level/LevelRegistry.hx b/source/funkin/data/level/LevelRegistry.hx
index 75b0b11f6..b5c15de0f 100644
--- a/source/funkin/data/level/LevelRegistry.hx
+++ b/source/funkin/data/level/LevelRegistry.hx
@@ -30,6 +30,7 @@ class LevelRegistry extends BaseRegistry<Level, LevelData>
     // JsonParser does not take type parameters,
     // otherwise this function would be in BaseRegistry.
     var parser = new json2object.JsonParser<LevelData>();
+    parser.ignoreUnknownVariables = false;
 
     switch (loadEntryFile(id))
     {
@@ -57,6 +58,7 @@ class LevelRegistry extends BaseRegistry<Level, LevelData>
   public function parseEntryDataRaw(contents:String, ?fileName:String):Null<LevelData>
   {
     var parser = new json2object.JsonParser<LevelData>();
+    parser.ignoreUnknownVariables = false;
     parser.fromJson(contents, fileName);
 
     if (parser.errors.length > 0)
diff --git a/source/funkin/data/notestyle/NoteStyleRegistry.hx b/source/funkin/data/notestyle/NoteStyleRegistry.hx
index 4255a644b..ffb9bf490 100644
--- a/source/funkin/data/notestyle/NoteStyleRegistry.hx
+++ b/source/funkin/data/notestyle/NoteStyleRegistry.hx
@@ -35,6 +35,7 @@ class NoteStyleRegistry extends BaseRegistry<NoteStyle, NoteStyleData>
     // JsonParser does not take type parameters,
     // otherwise this function would be in BaseRegistry.
     var parser = new json2object.JsonParser<NoteStyleData>();
+    parser.ignoreUnknownVariables = false;
 
     switch (loadEntryFile(id))
     {
@@ -62,6 +63,7 @@ class NoteStyleRegistry extends BaseRegistry<NoteStyle, NoteStyleData>
   public function parseEntryDataRaw(contents:String, ?fileName:String):Null<NoteStyleData>
   {
     var parser = new json2object.JsonParser<NoteStyleData>();
+    parser.ignoreUnknownVariables = false;
     parser.fromJson(contents, fileName);
 
     if (parser.errors.length > 0)
diff --git a/source/funkin/data/song/SongData.hx b/source/funkin/data/song/SongData.hx
index 7886ada4f..600871e2f 100644
--- a/source/funkin/data/song/SongData.hx
+++ b/source/funkin/data/song/SongData.hx
@@ -747,7 +747,7 @@ class SongNoteDataRaw
   /**
    * The kind of the note.
    * This can allow the note to include information used for custom behavior.
-   * Defaults to blank or `"normal"`.
+   * Defaults to blank or `Constants.DEFAULT_DIFFICULTY`.
    */
   @:alias("k")
   @:default("normal")
diff --git a/source/funkin/data/song/SongDataUtils.hx b/source/funkin/data/song/SongDataUtils.hx
index 4ae4b1426..309676884 100644
--- a/source/funkin/data/song/SongDataUtils.hx
+++ b/source/funkin/data/song/SongDataUtils.hx
@@ -230,6 +230,7 @@ class SongDataUtils
     trace('Read ${notesString.length} characters from clipboard.');
 
     var parser = new json2object.JsonParser<SongClipboardItems>();
+    parser.ignoreUnknownVariables = false;
     parser.fromJson(notesString, 'clipboard');
     if (parser.errors.length > 0)
     {
diff --git a/source/funkin/data/song/SongRegistry.hx b/source/funkin/data/song/SongRegistry.hx
index 850654eb7..5a0835f57 100644
--- a/source/funkin/data/song/SongRegistry.hx
+++ b/source/funkin/data/song/SongRegistry.hx
@@ -126,6 +126,8 @@ class SongRegistry extends BaseRegistry<Song, SongMetadata>
     variation = variation == null ? Constants.DEFAULT_VARIATION : variation;
 
     var parser = new json2object.JsonParser<SongMetadata>();
+    parser.ignoreUnknownVariables = false;
+
     switch (loadEntryMetadataFile(id, variation))
     {
       case {fileName: fileName, contents: contents}:
@@ -147,6 +149,7 @@ class SongRegistry extends BaseRegistry<Song, SongMetadata>
     variation = variation == null ? Constants.DEFAULT_VARIATION : variation;
 
     var parser = new json2object.JsonParser<SongMetadata>();
+    parser.ignoreUnknownVariables = false;
     parser.fromJson(contents, fileName);
 
     if (parser.errors.length > 0)
@@ -206,6 +209,8 @@ class SongRegistry extends BaseRegistry<Song, SongMetadata>
     variation = variation == null ? Constants.DEFAULT_VARIATION : variation;
 
     var parser = new json2object.JsonParser<SongMetadata_v2_1_0>();
+    parser.ignoreUnknownVariables = false;
+
     switch (loadEntryMetadataFile(id, variation))
     {
       case {fileName: fileName, contents: contents}:
@@ -226,6 +231,8 @@ class SongRegistry extends BaseRegistry<Song, SongMetadata>
     variation = variation == null ? Constants.DEFAULT_VARIATION : variation;
 
     var parser = new json2object.JsonParser<SongMetadata_v2_0_0>();
+    parser.ignoreUnknownVariables = false;
+
     switch (loadEntryMetadataFile(id, variation))
     {
       case {fileName: fileName, contents: contents}:
@@ -244,6 +251,7 @@ class SongRegistry extends BaseRegistry<Song, SongMetadata>
   function parseEntryMetadataRaw_v2_1_0(contents:String, ?fileName:String = 'raw'):Null<SongMetadata>
   {
     var parser = new json2object.JsonParser<SongMetadata_v2_1_0>();
+    parser.ignoreUnknownVariables = false;
     parser.fromJson(contents, fileName);
 
     if (parser.errors.length > 0)
@@ -257,6 +265,7 @@ class SongRegistry extends BaseRegistry<Song, SongMetadata>
   function parseEntryMetadataRaw_v2_0_0(contents:String, ?fileName:String = 'raw'):Null<SongMetadata>
   {
     var parser = new json2object.JsonParser<SongMetadata_v2_0_0>();
+    parser.ignoreUnknownVariables = false;
     parser.fromJson(contents, fileName);
 
     if (parser.errors.length > 0)
@@ -272,6 +281,8 @@ class SongRegistry extends BaseRegistry<Song, SongMetadata>
     variation = variation == null ? Constants.DEFAULT_VARIATION : variation;
 
     var parser = new json2object.JsonParser<SongMusicData>();
+    parser.ignoreUnknownVariables = false;
+
     switch (loadMusicDataFile(id, variation))
     {
       case {fileName: fileName, contents: contents}:
@@ -291,6 +302,7 @@ class SongRegistry extends BaseRegistry<Song, SongMetadata>
   public function parseMusicDataRaw(contents:String, ?fileName:String = 'raw'):Null<SongMusicData>
   {
     var parser = new json2object.JsonParser<SongMusicData>();
+    parser.ignoreUnknownVariables = false;
     parser.fromJson(contents, fileName);
 
     if (parser.errors.length > 0)
@@ -334,6 +346,7 @@ class SongRegistry extends BaseRegistry<Song, SongMetadata>
     variation = variation == null ? Constants.DEFAULT_VARIATION : variation;
 
     var parser = new json2object.JsonParser<SongChartData>();
+    parser.ignoreUnknownVariables = false;
 
     switch (loadEntryChartFile(id, variation))
     {
@@ -356,6 +369,7 @@ class SongRegistry extends BaseRegistry<Song, SongMetadata>
     variation = variation == null ? Constants.DEFAULT_VARIATION : variation;
 
     var parser = new json2object.JsonParser<SongChartData>();
+    parser.ignoreUnknownVariables = false;
     parser.fromJson(contents, fileName);
 
     if (parser.errors.length > 0)
diff --git a/source/funkin/data/song/importer/ChartManifestData.hx b/source/funkin/data/song/importer/ChartManifestData.hx
index 0c7d2f0b0..dd0d28479 100644
--- a/source/funkin/data/song/importer/ChartManifestData.hx
+++ b/source/funkin/data/song/importer/ChartManifestData.hx
@@ -68,6 +68,7 @@ class ChartManifestData
   public static function deserialize(contents:String):Null<ChartManifestData>
   {
     var parser = new json2object.JsonParser<ChartManifestData>();
+    parser.ignoreUnknownVariables = false;
     parser.fromJson(contents, 'manifest.json');
 
     if (parser.errors.length > 0)
diff --git a/source/funkin/data/song/importer/FNFLegacyData.hx b/source/funkin/data/song/importer/FNFLegacyData.hx
index 5b75368c9..52380d344 100644
--- a/source/funkin/data/song/importer/FNFLegacyData.hx
+++ b/source/funkin/data/song/importer/FNFLegacyData.hx
@@ -19,7 +19,8 @@ class LegacySongData
 
   @:jcustomparse(funkin.data.DataParse.eitherLegacyScrollSpeeds)
   public var speed:Either<Float, LegacyScrollSpeeds>;
-  public var stageDefault:String;
+  @:optional
+  public var stageDefault:Null<String>;
   public var bpm:Float;
 
   @:jcustomparse(funkin.data.DataParse.eitherLegacyNoteData)
diff --git a/source/funkin/data/song/importer/FNFLegacyImporter.hx b/source/funkin/data/song/importer/FNFLegacyImporter.hx
index ee68513dc..ab2abda8e 100644
--- a/source/funkin/data/song/importer/FNFLegacyImporter.hx
+++ b/source/funkin/data/song/importer/FNFLegacyImporter.hx
@@ -14,6 +14,7 @@ class FNFLegacyImporter
   public static function parseLegacyDataRaw(input:String, fileName:String = 'raw'):FNFLegacyData
   {
     var parser = new json2object.JsonParser<FNFLegacyData>();
+    parser.ignoreUnknownVariables = true; // Set to true to ignore extra variables that might be included in the JSON.
     parser.fromJson(input, fileName);
 
     if (parser.errors.length > 0)
@@ -185,15 +186,34 @@ class FNFLegacyImporter
     return result;
   }
 
+  static final STRUMLINE_SIZE = 4;
+
   static function migrateNoteSections(input:Array<LegacyNoteSection>):Array<SongNoteData>
   {
     var result:Array<SongNoteData> = [];
 
     for (section in input)
     {
+      var mustHitSection = section.mustHitSection ?? false;
       for (note in section.sectionNotes)
       {
-        result.push(new SongNoteData(note.time, note.data, note.length, note.getKind()));
+        // Handle the dumb logic for mustHitSection.
+        var noteData = note.data;
+
+        // Flip notes if mustHitSection is FALSE (not true lol).
+        if (!mustHitSection)
+        {
+          if (noteData >= STRUMLINE_SIZE)
+          {
+            noteData -= STRUMLINE_SIZE;
+          }
+          else
+          {
+            noteData += STRUMLINE_SIZE;
+          }
+        }
+
+        result.push(new SongNoteData(note.time, noteData, note.length, note.getKind()));
       }
     }
 
diff --git a/tests/unit/source/funkin/data/BaseRegistryTest.hx b/tests/unit/source/funkin/data/BaseRegistryTest.hx
index 0be932d35..5f837ba97 100644
--- a/tests/unit/source/funkin/data/BaseRegistryTest.hx
+++ b/tests/unit/source/funkin/data/BaseRegistryTest.hx
@@ -156,6 +156,7 @@ class MyTypeRegistry extends BaseRegistry<MyType, MyTypeData>
     // JsonParser does not take type parameters,
     // otherwise this function would be in BaseRegistry.
     var parser = new json2object.JsonParser<MyTypeData>();
+    parser.ignoreUnknownVariables = false;
 
     switch (loadEntryFile(id))
     {
@@ -181,6 +182,7 @@ class MyTypeRegistry extends BaseRegistry<MyType, MyTypeData>
     // JsonParser does not take type parameters,
     // otherwise this function would be in BaseRegistry.
     var parser = new json2object.JsonParser<MyTypeData_v0_1_x>();
+    parser.ignoreUnknownVariables = false;
 
     switch (loadEntryFile(id))
     {