diff --git a/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/Presenter.java b/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/Presenter.java
index 0256f33..a87e55f 100644
--- a/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/Presenter.java
+++ b/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/Presenter.java
@@ -4,6 +4,10 @@
 import rx.Observable;
 
 public class Presenter<E> extends RxPresenter<E> {
+    /*
+     *  fixes RxPresenter view is null bug
+     *  > call viewIfExists() instead of view()
+     */
     public Observable<E> viewIfExists() {
         return view().filter(view -> view != null);
     }
diff --git a/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/game/GameView.java b/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/game/GameView.java
index 7271965..8826103 100644
--- a/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/game/GameView.java
+++ b/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/game/GameView.java
@@ -9,6 +9,9 @@
 import kotlin.Pair;
 
 public interface GameView {
+    /*
+     *  shows Game Board with fields of appropriate size
+     */
     void showGameBoard(Board gameBoard, int gameSize);
 
     /*
@@ -27,5 +30,8 @@ public interface GameView {
      */
     void highlightWrongFields(List<Pair<Integer, Integer>> pairs);
 
+    /*
+     *  updates TextView percent_counter with corresponding data
+     */
     void updatePercentStatus(int percent);
 }
diff --git a/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/main/MainView.java b/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/main/MainView.java
index 9eeba2f..7a55e28 100644
--- a/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/main/MainView.java
+++ b/app/src/main/java/net/zdendukmonarezio/takuzu/presentation/main/MainView.java
@@ -1,5 +1,8 @@
 package net.zdendukmonarezio.takuzu.presentation.main;
 
 interface MainView {
+    /*
+     * updates TextView score with appropriate data
+     */
     public void updateScore();
 }