diff --git a/lib/al/Library/Camera/ICameraInput.h b/lib/al/Library/Camera/ICameraInput.h
index 5b8f7efb..d9fb5e5e 100644
--- a/lib/al/Library/Camera/ICameraInput.h
+++ b/lib/al/Library/Camera/ICameraInput.h
@@ -6,14 +6,14 @@ namespace al {
 
 class ICameraInput {
 public:
-    virtual void calcInputStick(sead::Vector2f* inputStick) const;
-    virtual bool isTriggerReset() const;
-    virtual bool isHoldZoom() const;
+    virtual void calcInputStick(sead::Vector2f* inputStick) const = 0;
+    virtual bool isTriggerReset() const = 0;
+    virtual bool isHoldZoom() const = 0;
 
     virtual bool tryCalcSnapShotMoveStick(sead::Vector2f* moveStick) const { return false; }
 
-    virtual bool isHoldSnapShotZoomIn() const;
-    virtual bool isHoldSnapShotZoomOut() const;
+    virtual bool isHoldSnapShotZoomIn() const = 0;
+    virtual bool isHoldSnapShotZoomOut() const = 0;
 
     virtual bool isHoldSnapShotRollLeft() const { return false; }
 
diff --git a/lib/al/Library/Ranking/IUseRanking.h b/lib/al/Library/Ranking/IUseRanking.h
index e4c442bf..7b8856a7 100644
--- a/lib/al/Library/Ranking/IUseRanking.h
+++ b/lib/al/Library/Ranking/IUseRanking.h
@@ -5,7 +5,8 @@ class RankingDirector;
 
 class IUseRanking {
 public:
-    virtual RankingDirector* getRankingDirector() const;
-    virtual bool isAvailableRanking() const;
+    virtual RankingDirector* getRankingDirector() const = 0;
+
+    virtual bool isAvailableRanking() const { return false; }
 };
 }  // namespace al
diff --git a/lib/al/Project/File/SoundItemEntry.h b/lib/al/Project/File/SoundItemEntry.h
index 8e4e0834..9c8fb878 100644
--- a/lib/al/Project/File/SoundItemEntry.h
+++ b/lib/al/Project/File/SoundItemEntry.h
@@ -14,10 +14,10 @@ namespace al {
 class IAudioResourceLoader {
 public:
     // TODO: placeholder functions
-    virtual void func_0();
-    virtual void func_8();
+    virtual void func_0() = 0;
+    virtual void func_8() = 0;
     // TODO: unknown parameter name
-    virtual bool tryLoad(u32 entryId, u32 unknown);
+    virtual bool tryLoad(u32 entryId, u32 unknown) = 0;
 };
 
 class SoundItemEntry : public FileEntryBase {