Why Your React App Lags but This Canvas Game Runs at 60FPS

We need to talk about the state of modern web development.

Yesterday, I profiled a simple corporate dashboard. It had a bundle size of 2.4MB (gzipped), took 3 seconds to reach Time to Interactive (TTI), and dropped frames whenever I opened a modal. It was built on a "modern" stack.

Then, strictly for "research purposes," I opened a tab running Vex 4. It loaded instantly. I ran it on a throttled network profile. I ran it on an aging Chromebook I keep for testing media queries.

The result? A buttery smooth 60fps. No jitter, no layout thrashing, just raw input response.

As developers, we often get lost in state management libraries and forget the raw power of the browser when we get out of its way. Here is a look at why "simple" HTML5 projects like Vex 4 are still the gold standard for runtime performance.

The Cost of the DOM

The main reason your SaaS app feels sluggish compared to a game like Vex 4 is the abstraction layer.

Modern apps rely heavily on DOM manipulation. Even with Virtual DOMs, you are essentially asking the browser to recalculate styles, compute layout, and repaint layers every time a state changes.

HTML5 games, on the other hand, often utilize the Canvas API. They operate in "Immediate Mode." They don't care about the DOM tree. They just wipe the screen and paint pixels.

The Loop

In Vex 4, the stick figure's physics aren't waiting for a React useEffect to trigger or a state to settle. It relies on the holy grail of web animation: requestAnimationFrame.

Here is a simplified pseudo-code of what’s happening under the hood compared to a typical app lifecycle:

// The Vex 4 Approach (Simplified)
const canvas = document.getElementById('game-stage');
const ctx = canvas.getContext('2d');

function gameLoop() {
  // 1. Physics Calculation (CPU bound, fast)
  player.updatePosition();
  collision.check();

  // 2. Rendering (GPU bound, optimized)
  ctx.clearRect(0, 0, width, height);
  player.draw(ctx);
  level.draw(ctx);

  // 3. The Recursion
  requestAnimationFrame(gameLoop);
}

// Kick it off
requestAnimationFrame(gameLoop);

There is no diffing. There is no reconciliation. Just a pure render cycle synced to the display's refresh rate.

Testing the "Unblocked" Experience

I used Vex 4 as a benchmark for testing input latency on constrained networks. Since it is an unblocked HTML5 project, it bypasses the need for heavy server-side rendering or client-side hydration.

The assets are lightweight. The logic is client-side.

I tested the game on a restrictive network environment (simulating a corporate VPN/firewall scenario). Because the game relies on standard web technologies without complex WebSocket handshakes or external heavy dependencies, it initializes immediately.

For developers looking to understand what "low overhead" actually looks and feels like, this is a solid reference implementation. It handles complex collision detection (spikes, saws, swimming physics) without the Garbage Collector causing noticeable stutter.

Conclusion

I'm not saying we should build our e-commerce checkout forms using Canvas (please don't). But we should appreciate the engineering elegance of these browser games.

They remind us that the browser is capable of incredible performance if we stop clogging the main thread.

Next time you are waiting for your npm install to finish, or you want to test if your browser’s hardware acceleration is actually working, take a look at this project. It is a great example of pure, unadulterated JavaScript performance.

👉 Live Demo / Performance Test: Run Vex 4 Here