These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Ghosts N Goblins
Demonic Spiders: RED fucking ARREMER. Just whisper these words to any G'n'G player to see them whimper in pain.
To make matters worse, you meet one about 25 seconds into the first level.
A lesser known strategy is to stop firing to lull Red Arremer into false security. once he lands and gets closer to you, fire away. He's still a close fight no matter what you do, though.