import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Label;
import java.awt.Panel;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.TextEvent;
import java.awt.event.TextListener;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.Calendar;

public class Game3D extends Applet implements ActionListener, TextListener {
  static final boolean isFreeware = true;
  
  MainGame game;
  
  Label hiScoreLabel;
  
  Label lblContinue;
  
  NumberLabel scoreWin;
  
  static boolean isLocal = false;
  
  int lang = 0;
  
  String[] bt1 = new String[] { "Regist your Hi-score", "};
  
  String[] contMsg = new String[] { "Push [C] key to start from this stage!!", "[C]key };
  
  String[] toStartMsg = new String[] { "Click this game screen or push [space] key!!", "};
  
  String[] clickMsg = new String[] { "Click!!", "};
  
  private String strSessionId_;
  
  private int sentScore_ = 0;
  
  private TextField txtName = new TextField("No name", 16);
  
  private Button btnInput = new Button("Ok");
  
  private boolean isModified_ = false;
  
  public void stop() {
    this.game.stop();
  }
  
  private void rankInit() {
    this.strSessionId_ = Long.toString(Calendar.getInstance().getTime().getTime());
  }
  
  private String decodeString(String paramString) {
    if (paramString.charAt(0) != 'Z')
      return paramString; 
    StringBuffer stringBuffer = new StringBuffer();
    for (byte b = 1; b < paramString.length(); b += 4) {
      int i = Integer.parseInt(paramString.substring(b, b + 4), 16);
      stringBuffer.append((char)i);
    } 
    return stringBuffer.toString();
  }
  
  private synchronized void sendScore(int paramInt, String paramString) {
    if (this.sentScore_ >= paramInt && !this.isModified_)
      return; 
    try {
      int i = paramInt % 8191 + paramInt % 237;
      System.out.println("...");
      String str1 = "regist.cgi?" + paramInt + "+" + i + "+" + encodeString(paramString) + "+" + this.strSessionId_;
      InputStream inputStream = (new URL(getCodeBase(), str1)).openStream();
      BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
      String str2 = bufferedReader.readLine();
      System.out.println(str2);
      this.sentScore_ = paramInt;
    } catch (Exception exception) {
      System.out.println(exception);
    } 
    loadRanking();
  }
  
  public static void main(String[] paramArrayOfString) {
    isLocal = true;
    Game3D game3D = new Game3D();
    AppFrame appFrame = new AppFrame(game3D, "Jet slalom");
    appFrame.show();
    appFrame.setLayout(new BorderLayout());
    appFrame.add("Center", game3D);
    game3D.init();
    appFrame.validate();
    appFrame.pack();
    game3D.start();
  }
  
  public void actionPerformed(ActionEvent paramActionEvent) {
    sendScore(this.game.getHiScore(), this.txtName.getText());
    this.game.requestFocus();
  }
  
  public void start() {
    this.game.start();
    this.game.startGame(1, false);
  }
  
  public void init() {
    if (!isLocal) {
      String str = getParameter("LANG");
      if (!isLocal && str != null && str.equals("JP"))
        this.lang = 1; 
    } 
    setLayout(new BorderLayout());
    setBackground(new Color(160, 208, 176));
    this.scoreWin = new NumberLabel(64, 12);
    this.lblContinue = new Label("            ");
    Panel panel = new Panel(new FlowLayout(0, 5, 0));
    panel.setLayout(new FlowLayout());
    panel.add(new Label("Score:"));
    panel.add(this.scoreWin);
    panel.add(new Label("Continue penalty:"));
    panel.add(this.lblContinue);
    add("North", panel);
    this.hiScoreLabel = new Label("Your Hi-score:0         ");
    add("South", this.hiScoreLabel);
    this.game = new MainGame(this);
    add("Center", this.game);
    this.game.init();
    this.game.requestFocus();
    invalidate();
    validate();
  }
  
  public void textValueChanged(TextEvent paramTextEvent) {
    this.isModified_ = true;
  }
  
  private synchronized void loadRanking() {
    // Byte code:
    //   0: bipush #20
    //   2: anewarray java/lang/String
    //   5: astore_1
    //   6: iconst_0
    //   7: istore_2
    //   8: aload_1
    //   9: iload_2
    //   10: ldc_w ''
    //   13: aastore
    //   14: iinc #2, 1
    //   17: iload_2
    //   18: bipush #20
    //   20: if_icmplt -> 8
    //   23: new java/net/URL
    //   26: dup
    //   27: aload_0
    //   28: invokevirtual getCodeBase : ()Ljava/net/URL;
    //   31: ldc_w 'rank.dat'
    //   34: invokespecial <init> : (Ljava/net/URL;Ljava/lang/String;)V
    //   37: invokevirtual openStream : ()Ljava/io/InputStream;
    //   40: astore_3
    //   41: new java/io/BufferedReader
    //   44: dup
    //   45: new java/io/InputStreamReader
    //   48: dup
    //   49: aload_3
    //   50: invokespecial <init> : (Ljava/io/InputStream;)V
    //   53: invokespecial <init> : (Ljava/io/Reader;)V
    //   56: astore #4
    //   58: iconst_0
    //   59: istore_2
    //   60: aload #4
    //   62: invokevirtual readLine : ()Ljava/lang/String;
    //   65: astore #5
    //   67: aload #5
    //   69: ifnull -> 208
    //   72: new java/util/StringTokenizer
    //   75: dup
    //   76: aload #5
    //   78: ldc_w ','
    //   81: invokespecial <init> : (Ljava/lang/String;Ljava/lang/String;)V
    //   84: astore #6
    //   86: ldc_w '000000 : ???'
    //   89: astore #7
    //   91: aload #6
    //   93: invokevirtual hasMoreTokens : ()Z
    //   96: ifeq -> 194
    //   99: aload #6
    //   101: invokevirtual nextToken : ()Ljava/lang/String;
    //   104: invokestatic parseInt : (Ljava/lang/String;)I
    //   107: istore #8
    //   109: aload #6
    //   111: invokevirtual hasMoreTokens : ()Z
    //   114: ifeq -> 194
    //   117: aload_0
    //   118: aload #6
    //   120: invokevirtual nextToken : ()Ljava/lang/String;
    //   123: invokespecial decodeString : (Ljava/lang/String;)Ljava/lang/String;
    //   126: astore #9
    //   128: new java/lang/StringBuffer
    //   131: dup
    //   132: invokespecial <init> : ()V
    //   135: ldc_w '000000'
    //   138: invokevirtual append : (Ljava/lang/String;)Ljava/lang/StringBuffer;
    //   141: iload #8
    //   143: invokevirtual append : (I)Ljava/lang/StringBuffer;
    //   146: invokevirtual toString : ()Ljava/lang/String;
    //   149: astore #10
    //   151: aload #10
    //   153: aload #10
    //   155: invokevirtual length : ()I
    //   158: bipush #6
    //   160: isub
    //   161: invokevirtual substring : (I)Ljava/lang/String;
    //   164: astore #10
    //   166: new java/lang/StringBuffer
    //   169: dup
    //   170: invokespecial <init> : ()V
    //   173: aload #10
    //   175: invokevirtual append : (Ljava/lang/String;)Ljava/lang/StringBuffer;
    //   178: ldc_w ' : '
    //   181: invokevirtual append : (Ljava/lang/String;)Ljava/lang/StringBuffer;
    //   184: aload #9
    //   186: invokevirtual append : (Ljava/lang/String;)Ljava/lang/StringBuffer;
    //   189: invokevirtual toString : ()Ljava/lang/String;
    //   192: astore #7
    //   194: aload_1
    //   195: iload_2
    //   196: aload #7
    //   198: aastore
    //   199: iinc #2, 1
    //   202: iload_2
    //   203: bipush #20
    //   205: if_icmplt -> 60
    //   208: aload_0
    //   209: getfield game : LMainGame;
    //   212: aload_1
    //   213: invokevirtual setHiScoreInfo : ([Ljava/lang/String;)V
    //   216: getstatic java/lang/System.out : Ljava/io/PrintStream;
    //   219: ldc_w 'Success to load hi-score list.'
    //   222: invokevirtual println : (Ljava/lang/String;)V
    //   225: return
    //   226: astore_3
    //   227: getstatic java/lang/System.out : Ljava/io/PrintStream;
    //   230: ldc_w 'Fail to load hi-score list.'
    //   233: invokevirtual println : (Ljava/lang/String;)V
    //   236: aload_3
    //   237: invokevirtual printStackTrace : ()V
    //   240: return
    // Exception table:
    //   from   to  target  type
    //   23 225 226 java/lang/Exception
  }
  
  private String encodeString(String paramString) {
    StringBuffer stringBuffer = new StringBuffer("Z");
    for (byte b = 0; b < paramString.length(); b++) {
      char c = paramString.charAt(b);
      String str = "0000" + Integer.toHexString(c);
      str = str.substring(str.length() - 4);
      stringBuffer.append(str);
    } 
    return stringBuffer.toString();
  }
  
  public synchronized void endGame() {
    sendScore(this.game.getHiScore(), this.txtName.getText());
  }
}

That code outputs the following applet as seen on the top left:

enter image description here

As you can see, at that size, the game is playable but far from enjoyable; somehow you need the illusion of space to inspire hope and fun (dodging of the pylons). There are other versions of the game, but these miss the classic level progression, as well, there was a Turbo Mode in the original which flies the ship at 10X the speed while a key is pressed if I remember correctly.

The game is decommissioned and abandoned since the early 2000s so don’t feel too bad about reviving a classic. But actually this is only one of many project files, but the one that encapsolates the game.

You can maximize applets to your heart’s content, but you’d simply be maximizing the window, the game would remain the same size as shown. Also yes, you can make it bigger with magnifying glass and DPI, but this affects the quality of the graphics; pylons and distance become unpleasantly jagged, and beyond DPI of 175% Windows makes you sign out and in; this is annoying. This is why you were provided a code snippet. I am not that experienced in Java, and Java is Big for a programming language; lots of libraries. I am seeking to make the game resolution a vertical resolution of 1800 and horizontal 1080; this is mostly so the Windows taskbar is out of the way. The way the game appears to be coded to my eyes is “fit everything in the smallest possible window, I am an applet”.

Beyond my level of expertise.