diff --git a/src/LiquidCode.Tester.Worker/Services/KotlinCompilationServiceIsolate.cs b/src/LiquidCode.Tester.Worker/Services/KotlinCompilationServiceIsolate.cs
index 781ec9a..a3160a6 100644
--- a/src/LiquidCode.Tester.Worker/Services/KotlinCompilationServiceIsolate.cs
+++ b/src/LiquidCode.Tester.Worker/Services/KotlinCompilationServiceIsolate.cs
@@ -15,7 +15,7 @@ public class KotlinCompilationServiceIsolate : ICompilationService
     private readonly IsolateBoxPool _boxPool;
 
     private const int CompilationTimeLimitSeconds = 30;
-    private const int CompilationMemoryLimitMb = 512;
+    private const int CompilationMemoryLimitMb = 1024; // Kotlin uses JVM, needs more memory
 
     public KotlinCompilationServiceIsolate(
         ILogger<KotlinCompilationServiceIsolate> logger,
@@ -39,7 +39,21 @@ public class KotlinCompilationServiceIsolate : ICompilationService
 
         try
         {
-            await File.WriteAllTextAsync(sourceFilePath, sourceCode);
+            // Normalize line endings
+            var normalizedSourceCode = sourceCode
+                .Replace("\\r\\n", "\n")  // Handle escaped \r\n (literal text "\\r\\n")
+                .Replace("\\n", "\n")      // Handle escaped \n (literal text "\\n")
+                .Replace("\\r", "\n")      // Handle escaped \r (literal text "\\r")
+                .Replace("\r\n", "\n")     // Handle actual Windows line endings
+                .Replace("\r", "\n");      // Handle actual Mac line endings
+
+            _logger.LogDebug("Source code length: {Length}, normalized length: {NormalizedLength}, line count: {LineCount}",
+                sourceCode.Length, normalizedSourceCode.Length, normalizedSourceCode.Split('\n').Length);
+
+            _logger.LogDebug("First 200 chars of source: {Preview}",
+                normalizedSourceCode.Length > 200 ? normalizedSourceCode.Substring(0, 200) : normalizedSourceCode);
+
+            await File.WriteAllTextAsync(sourceFilePath, normalizedSourceCode);
             return await CompileFileInIsolateAsync(sourceFilePath, jarFilePath, version);
         }
         catch (Exception ex)
@@ -89,6 +103,7 @@ public class KotlinCompilationServiceIsolate : ICompilationService
             arguments.Add($"/box/{jarFileName}");
 
             var stderrFilePath = Path.Combine(boxDir, "compile_stderr.txt");
+            var stdoutFilePath = Path.Combine(boxDir, "compile_stdout.txt");
 
             var isolateResult = await _isolateService.RunAsync(new IsolateRunOptions
             {
@@ -98,9 +113,10 @@ public class KotlinCompilationServiceIsolate : ICompilationService
                 TimeLimitSeconds = CompilationTimeLimitSeconds,
                 WallTimeLimitSeconds = CompilationTimeLimitSeconds * 2,
                 MemoryLimitKb = CompilationMemoryLimitMb * 1024,
-                StackLimitKb = 256 * 1024,
-                ProcessLimit = 10,
+                StackLimitKb = 128 * 1024, // 128MB stack per process
+                ProcessLimit = 64, // Kotlin uses JVM, needs many threads/processes
                 EnableNetwork = false,
+                StdoutFile = stdoutFilePath,
                 StderrFile = stderrFilePath,
                 WorkingDirectory = "/box",
                 DirectoryBindings = new List<DirectoryBinding>
@@ -120,13 +136,34 @@ public class KotlinCompilationServiceIsolate : ICompilationService
             });
 
             var compilerOutput = string.Empty;
+
+            // Read stdout (kotlinc may output errors there)
+            if (File.Exists(stdoutFilePath))
+            {
+                var stdoutContent = await File.ReadAllTextAsync(stdoutFilePath);
+                if (!string.IsNullOrWhiteSpace(stdoutContent))
+                {
+                    compilerOutput = stdoutContent;
+                }
+            }
+
+            // Read stderr
             if (File.Exists(stderrFilePath))
             {
-                compilerOutput = await File.ReadAllTextAsync(stderrFilePath);
+                var stderrContent = await File.ReadAllTextAsync(stderrFilePath);
+                if (!string.IsNullOrWhiteSpace(stderrContent))
+                {
+                    compilerOutput = string.IsNullOrEmpty(compilerOutput)
+                        ? stderrContent
+                        : $"{compilerOutput}\n{stderrContent}";
+                }
             }
+
             if (!string.IsNullOrEmpty(isolateResult.ErrorOutput))
             {
-                compilerOutput = $"{compilerOutput}\n{isolateResult.ErrorOutput}".Trim();
+                compilerOutput = string.IsNullOrEmpty(compilerOutput)
+                    ? isolateResult.ErrorOutput
+                    : $"{compilerOutput}\n{isolateResult.ErrorOutput}";
             }
 
             if (isolateResult.TimeLimitExceeded)