diff --git a/src/Chip8.Replay/BenchmarkResult.cs b/src/Chip8.Replay/BenchmarkResult.cs
new file mode 100644
index 0000000..5a744e4
--- /dev/null
+++ b/src/Chip8.Replay/BenchmarkResult.cs
@@ -0,0 +1,58 @@
+using System.Globalization;
+using System.Text;
+
+namespace Chip8.Replay;
+
+public sealed class BenchmarkResult
+{
+    public string romName { get; }
+    public int stepsExecuted { get; }
+    public int framesExecuted { get; }
+    public double elapsedMilliseconds { get; }
+    public ulong framebufferHash { get; }
+    public bool exited { get; }
+
+    public BenchmarkResult(
+        string romName,
+        int stepsExecuted,
+        int framesExecuted,
+        double elapsedMilliseconds,
+        ulong framebufferHash,
+        bool exited)
+    {
+        this.romName = romName;
+        this.stepsExecuted = stepsExecuted;
+        this.framesExecuted = framesExecuted;
+        this.elapsedMilliseconds = elapsedMilliseconds;
+        this.framebufferHash = framebufferHash;
+        this.exited = exited;
+    }
+
+    public double elapsedSeconds => elapsedMilliseconds / 1000.0;
+
+    public double instructionsPerSecond =>
+        elapsedMilliseconds > 0 ? stepsExecuted / elapsedSeconds : double.NaN;
+
+    public double framesPerSecond =>
+        elapsedMilliseconds > 0 ? framesExecuted / elapsedSeconds : double.NaN;
+
+    public string format()
+    {
+        var builder = new StringBuilder();
+        builder.Append(romName).Append(": ");
+        builder.Append(stepsExecuted).Append(" steps / ");
+        builder.Append(framesExecuted).Append(" frames in ");
+        builder.Append(elapsedMilliseconds.ToString("F2", CultureInfo.InvariantCulture)).Append(" ms");
+        if (elapsedMilliseconds > 0)
+        {
+            builder.Append(" (");
+            builder.Append((instructionsPerSecond / 1_000_000.0).ToString("F2", CultureInfo.InvariantCulture));
+            builder.Append(" Mips, ");
+            builder.Append(framesPerSecond.ToString("F0", CultureInfo.InvariantCulture));
+            builder.Append(" fps)");
+        }
+        return builder.ToString();
+    }
+
+    public override string ToString() => format();
+}
diff --git a/src/Chip8.Replay/RomExpectation.cs b/src/Chip8.Replay/RomExpectation.cs
new file mode 100644
index 0000000..c8f6c56
--- /dev/null
+++ b/src/Chip8.Replay/RomExpectation.cs
@@ -0,0 +1,47 @@
+using Chip8.Core;
+
+namespace Chip8.Replay;
+
+public sealed class RomExpectation
+{
+    public string romName { get; }
+    public Platform platform { get; }
+    public Quirks quirks { get; }
+    public int cycles { get; }
+    public int instructionsPerFrame { get; }
+    public int randomSeed { get; }
+    public int minLitPixels { get; }
+    public int maxLitPixels { get; }
+    public ulong? framebufferHash { get; }
+    public string description { get; }
+
+    public RomExpectation(
+        string romName,
+        Platform platform,
+        Quirks quirks,
+        int cycles,
+        int minLitPixels,
+        int maxLitPixels,
+        int instructionsPerFrame = 11,
+        int randomSeed = 1,
+        ulong? framebufferHash = null,
+        string description = "")
+    {
+        this.romName = romName;
+        this.platform = platform;
+        this.quirks = quirks;
+        this.cycles = cycles;
+        this.minLitPixels = minLitPixels;
+        this.maxLitPixels = maxLitPixels;
+        this.instructionsPerFrame = instructionsPerFrame;
+        this.randomSeed = randomSeed;
+        this.framebufferHash = framebufferHash;
+        this.description = description;
+    }
+
+    public bool litPixelsInRange(int litPixels) => litPixels >= minLitPixels && litPixels <= maxLitPixels;
+
+    public RomExpectation withHash(ulong hash) => new RomExpectation(
+        romName, platform, quirks, cycles, minLitPixels, maxLitPixels,
+        instructionsPerFrame, randomSeed, hash, description);
+}
diff --git a/src/Chip8.Replay/TestRomResult.cs b/src/Chip8.Replay/TestRomResult.cs
new file mode 100644
index 0000000..60d19b3
--- /dev/null
+++ b/src/Chip8.Replay/TestRomResult.cs
@@ -0,0 +1,59 @@
+using System.Text;
+
+namespace Chip8.Replay;
+
+public sealed class TestRomResult
+{
+    public string romName { get; }
+    public bool passed { get; }
+    public int litPixels { get; }
+    public int minLitPixels { get; }
+    public int maxLitPixels { get; }
+    public ulong framebufferHash { get; }
+    public ulong registerHash { get; }
+    public int cyclesExecuted { get; }
+    public bool exited { get; }
+    public string detail { get; }
+
+    public TestRomResult(
+        string romName,
+        bool passed,
+        int litPixels,
+        int minLitPixels,
+        int maxLitPixels,
+        ulong framebufferHash,
+        ulong registerHash,
+        int cyclesExecuted,
+        bool exited,
+        string detail)
+    {
+        this.romName = romName;
+        this.passed = passed;
+        this.litPixels = litPixels;
+        this.minLitPixels = minLitPixels;
+        this.maxLitPixels = maxLitPixels;
+        this.framebufferHash = framebufferHash;
+        this.registerHash = registerHash;
+        this.cyclesExecuted = cyclesExecuted;
+        this.exited = exited;
+        this.detail = detail;
+    }
+
+    public string format()
+    {
+        var builder = new StringBuilder();
+        builder.Append(passed ? "PASS " : "FAIL ");
+        builder.Append(romName);
+        builder.Append(" lit=").Append(litPixels);
+        builder.Append(" range=[").Append(minLitPixels).Append("..").Append(maxLitPixels).Append(']');
+        builder.Append(" fb=").Append(FramebufferHash.format(framebufferHash));
+        builder.Append(" cycles=").Append(cyclesExecuted);
+        if (detail.Length > 0)
+        {
+            builder.Append(" (").Append(detail).Append(')');
+        }
+        return builder.ToString();
+    }
+
+    public override string ToString() => format();
+}