Area 1 (US: Round 37)[edit]
This area contains fifty-five Special Invaders (eleven of each of Types 14 to 18), in a horizontally-moving formation; the song that you will be hearing from the Yamaha YM-2610 during this world is also identical to that of World 4A before it.
Area 2 (US: Round 38)[edit]
This area contains fourteen Type 7 Circling Invaders and eighteen Type 8 Circling Invaders (in, as their name implies, a circling formation); the formation was first employed by the Flector in the first stage of Return of the Invaders (1985).
Area 3 (US: Round 39)[edit]
This area contains: eleven Type 19 Special Invaders, six Type 20 Special Invaders, eleven Type 21 Special Invaders, six Type 22 Special Invaders and eleven Type 23 Special Invaders; when one gets hit for the first time, it will split into two, adding to fifty-six. Once you clear this, a remix of the first "boss" theme will be heard from the Yamaha YM-2610.
Area 4 (US: Round 40)[edit]
As the (third, if you are playing the US version) Boss Invader comes down into view, from the top of the screen, it shall fire six missiles down at the two CG30s from its sides; the eye (which is actually a shuriken) is its only vulnerable point and it will occasionally drop it before it returns to it like a boomerang. Once you have hit the shuriken forty-five times, it will explode and fall off the bottom of the screen, and the player who registered the killer shot will (once again, if you're playing that US version), receive 70000 points - and you will then proceed to the third "Cattle Mutilation", regardless of which version you are playing. This is the last "Cattle Mutilation" of the game, so the UFOs will try everything they can.