refined the movement, only partly I still wanna do some touches so it feels better

src/main/java/dev/dvorakmortonxd/Game.java

@@ -60,7 +60,7 @@ public class Game extends JPanel implements ActionListener {
     /* defines the level which is used to determine what exactly shows (for example main menu is level 1),
        levelProgress which is only used for the animation from level 1 to level 2
        and fadeAnimation which is also used for the animation from level 1 to level 2                       */
-    public int level = 1;
+    public int level = 3;
     public boolean levelProgress = false; // this is used to make the transition from the Game menu to the game level look cool
     public int fadeAnimation = 0;
 
@@ -109,15 +109,24 @@ public class Game extends JPanel implements ActionListener {
     // defines the initial player variables
     public int playerX = 423;
     public int playerY = 310;
-    public int playerOldY = playerY;
+    public double playerXVelocity = 0;
+    public double playerYVelocity = 0;
+    public boolean leftHeld, rightHeld;
+
+    public static final double acceleration = 0.01;
+    public final double friction = 0.6;
+    public final double maxSpeed = 6.0;
+    public final double gravity = 1.0;
+    public final double jumpSpeed = -12.6;
+    public final double maxFall = 20.0;
+
     public int playerSizeX = 14*4;
     public int playerSizeY = 18*4;
     public String playerDirection = "none";
     public BufferedImage playerCurrentSprite;
     public int playerWalkingModifier = 5;
     public boolean playerOnFeet = true;
-    public boolean playerJumped = false;
+    public boolean playerActive = true;
-    public boolean playerActive = false;
     public int walkTick;
     public static int ticksPerFrame = 8;
     public static int[] walkCycle = {1, 0, 2, 0};

src/main/java/dev/dvorakmortonxd/input.java

@@ -14,26 +14,23 @@ public class input implements KeyListener {
                 case KeyEvent.VK_W:
                     m.playerDirection = "backward";
                     break;
-                case KeyEvent.VK_A:
+                case KeyEvent.VK_A, KeyEvent.VK_LEFT:
                     m.playerDirection = "left";
+                    m.leftHeld = true;
                     break;
                 case KeyEvent.VK_S:
                     m.playerDirection = "forward";
                     break;
-                case KeyEvent.VK_D:
+                case KeyEvent.VK_D, KeyEvent.VK_RIGHT:
                     m.playerDirection = "right";
+                    m.rightHeld = true;
                     break;
                 case KeyEvent.VK_SPACE:
-                    if (!m.playerJumped && m.playerOnFeet) {
+                    if (m.playerOnFeet) {
-                        m.playerJumped = true;
+                        m.playerYVelocity = m.jumpSpeed;
-                        m.playerOldY = m.playerY;
+                        m.playerOnFeet = false;
                     }
                     break;
-                /* ONLY FOR DEBUGGING BELOW
-                case KeyEvent.VK_A -> m.playerX -= m.playerWalkingModifier;
-                case KeyEvent.VK_D -> m.playerX += m.playerWalkingModifier;
-                case KeyEvent.VK_S -> m.playerY += 1;
-                case KeyEvent.VK_W -> m.playerY -= 1; */
             }
         }
         switch (e.getKeyCode()) {
@@ -49,10 +46,20 @@ public class input implements KeyListener {
     public void keyReleased(KeyEvent e) { // what happens when you let go of a key
         if (m.playerActive) {
             switch (e.getKeyCode()) {
-                case KeyEvent.VK_W -> m.playerDirection = "none";
+                case KeyEvent.VK_W:
-                case KeyEvent.VK_A -> m.playerDirection = "none";
+                    m.playerDirection = "none";
-                case KeyEvent.VK_S -> m.playerDirection = "none";
+                    break;
-                case KeyEvent.VK_D -> m.playerDirection = "none";
+                case KeyEvent.VK_A, KeyEvent.VK_LEFT:
+                    m.playerDirection = "none";
+                    m.leftHeld = false;
+                    break;
+                case KeyEvent.VK_S:
+                    m.playerDirection = "none";
+                    break;
+                case KeyEvent.VK_D, KeyEvent.VK_RIGHT:
+                    m.playerDirection = "none";
+                    m.rightHeld = false;
+                    break;
                 /* ONLY FOR DEBUGGING BELOW
                 case KeyEvent.VK_A -> m.playerX -= m.playerWalkingModifier;
                 case KeyEvent.VK_D -> m.playerX += m.playerWalkingModifier;

src/main/java/dev/dvorakmortonxd/update.java

@@ -14,6 +14,13 @@ public class update {
             default -> m.playerForward0;
         };
     }
+    public static double getGroundY(Game m) {
+        if (m.level == 3) {
+            if (m.playerX > 274 && m.playerX < 583) { return 338; } else { return 366; }
+        } else {
+            return m.windowHeight;
+        }
+    }
     static void performPerTick(Game m) {
         Random rand = new Random();
         m.starSize = rand.nextInt(2,4);
@@ -75,13 +82,35 @@ public class update {
             } else {
                 m.walkTick = 0;
             }
-            if (m.playerJumped) {
+            if (m.leftHeld && !m.rightHeld) {
-                m.playerOnFeet = false;
+                m.playerXVelocity -= m.acceleration;
-                m.playerY -= 20;
+            } else if (m.rightHeld && !m.leftHeld) {
-                if (m.playerOldY-80 >= m.playerY) { m.playerJumped = false; }
+                m.playerXVelocity +=m.acceleration;
+            } else {
+                if (m.playerXVelocity > 0) {
+                    m.playerXVelocity = Math.max(0, m.playerXVelocity - m.friction);
+                } else if (m.playerXVelocity < 0) {
+                    m.playerXVelocity = Math.min(0, m.playerXVelocity + m.friction);
+                }
             }
 
+            m.playerXVelocity = Math.clamp(m.playerXVelocity, -m.maxSpeed, m.maxSpeed);
+            m.playerX += m.playerXVelocity;
+            m.playerYVelocity = Math.min(m.playerYVelocity + m.gravity, m.maxFall);
+            m.playerY += m.playerYVelocity;
+
             // collisions
+
+            double groundY = getGroundY(m);
+            if (m.playerY >= groundY) {
+                m.playerY = (int) groundY;
+                m.playerYVelocity = 0;
+                m.playerOnFeet = true;
+            } else {
+                m.playerOnFeet = false;
+            }
+
+            /*
             if (m.level == 3 && (m.playerY < 338 || (m.playerX >= 583 || m.playerX <= 274) && m.playerY < 366)) {
                 m.playerY += 10;
                 m.playerOnFeet = false;
@@ -90,9 +119,9 @@ public class update {
                 m.playerOnFeet = true;
             } else {
                 m.playerOnFeet = true;
-            }
+            }*/
 
-            // update the player sprite based on direction and if hes walking and frame
+            // update the player sprite based on direction and if he's walking and frame
             m.playerCurrentSprite = spriteFor(m, m.playerDirection, frame);
             // first ship
             if (m.playerX < -m.playerSizeX || m.playerX > m.windowWidth) { m.level = 4; }