Pentablocks is a free online bullet-hell dodging game where you control a small dot navigating through relentless waves of sharp red pentagonal obstacles in a neon void. Inspired by the infamous red block sections from Slope and the evasion mechanics of Undertale battles, this browser game strips everything back to pure survival — no weapons, no health pickups, just you versus the patterns. Use WASD to move with pixel-precise control as obstacle barrages grow faster and more complex the longer you last.

The difficulty escalates quickly, forcing you to read incoming patterns and commit to clean movement lines rather than panic-dodging. Chaining perfect dodges feels genuinely satisfying, and unlockable modes give you fresh challenges once you've figured out the base rhythm. The minimalist neon aesthetic keeps visual noise low so your focus stays on the obstacles — exactly how a reflex game should work. Competing for high scores adds serious replay value, and each run rarely exceeds a few minutes, making it easy to squeeze in one more attempt.

Pentablocks is a perfect fit for fans of free online arcade games, browser-based reflex challenges, and skill games with no download required. Players who enjoy bullet-hell games, dodge survival games, or fast-paced 2D arcade games will find it immediately addictive. It also appeals to anyone chasing leaderboard scores in free .io-style games or looking for a tough but fair single-player skill test they can play instantly on any browser.