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.
Goddamned Bats: The cave stage has them. Although they don't fire at all, they tend to appear in groups. And if they fly off the left side of the screen... they come back in facing right, and try to fly into you again!
One of the enemies found in the final stage disables your Attack Drone by encasing it. Until your drone can shoot its way out, you'll have to rely on your regular weapon! Thankfully, you only encounter about 3-4 of them or so.
Nightmare Fuel: The biological design of the enemies and bizarre stages mean there's quite a lot of creepy stuff. The stage 2 boss in particular... (it's a giant rat-tail maggot)
And those walking hearts that shoot blood cells at you!
