Chain Reaction (World, Version 2.2, 1995.09.25)

First, familiarize yourself with the four playable fighters before you start your run: the blue Lightning is the all-around balanced option with average speed, spread fire, and a screen-clearing electro bomb ideal for new players; the red Firebrand has high speed, concentrated forward fire, and a flame bomb that deals massive damage to single bosses, perfect for score chasers; the green Titan is slow-moving but has wide area coverage fire and a shield bomb that blocks incoming projectiles for 5 seconds, great for navigating dense bullet patterns; the hidden purple Phantom, unlocked by holding the start button while selecting your fighter, has homing missiles and a chain reaction boost bomb that extends the radius of triggered explosions by 50% for maximum multipliers. The core chain reaction mechanic is your most important tool: always prioritize destroying marked red core enemies first whenever they appear on screen, as their explosion will take out every smaller enemy within a 300-pixel radius, and each consecutive enemy taken out in the chain increases your score multiplier by 0.5x, up to a maximum 10x multiplier that lasts for 10 seconds if you trigger a chain of 15 or more enemies. When fighting bosses, save at least one bomb for their second and third phases, as their bullet patterns become exponentially denser: if you see a boss flash red before firing a spread pattern, position yourself in the small gap between the first two bullet streams to avoid taking damage, as this pattern is consistent across all boss fights. The 2.2 World version’s hidden bonus stages trigger if you collect 10 golden "CR" power-ups across the first three stages: these stages have no enemy fire, only floating power cores that you can chain together for massive score gains, so save your bombs before entering these stages to trigger the largest possible chains. If you are aiming for the true ending, avoid using continues at all costs: even a single continue will lock you out of the fina