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.
Faux Symbolism: The group of alien spacecraft is shaped like a crucifix. You can even make out a shape that appears to be Jesus on it.
Narm: If this manga's not your thing, (and, let's face it, even if it is,) it'll come across as very silly.
Narm Charm: Sure, this manga might be silly, but the way every strange character and plot development is played completely seriously gives it an air of unreality that's actually a bit creepy and unnerving. No matter how narmy you find it, you will be frightened at least once.
So Bad, It's Good: This is generally how it's regarded in the western world. On the other hand, the Japanese tend to like it unironically.