We should be clearer about what's a hazard and what's an enemy. Many people seem to distinguish one from the other by thinking that hazards don't move. This is vague and has exceptions, however. For example, many hazards in Hot Air move, along with many other ones in different games. It has always been my view that enemies can be hurt, and hazards can't. Here are the current definitions for hazards and enemies:
An Enemy is a character who attempts to hurt the protagonist and eventually deplete their health. Enemies basically are characters that have eyes and/or mouth, and either move or somehow attack.
Hazards are areas in a game that cause danger to the player's character if made contact with. Often in Nitrome games, they are characterized by their immobility and lack of a face, and often cover great areas of the game.
This mostly says that enemies have faces, and hazards don't, in addition to hazards always being immobile. All the Hot Air hazards have faces. Why are Squish Blocks enemies if you can't kill them? You have to avoid them, which makes them hazards. All the Skywire obstacles are enemies, although, like the Squish Blocks, you can't kill them and have to avoid them.
There. I'm done lecturing everyone on better descriptions. I wish I could edit more. I'm really sorry. BTW, Santi, I like what you did with MediaWiki:Wikia.css a lot! Could you make my link black, or is it only for admins? It doesn't matter to me really, I just thought it was cool. Well, I wish I talked about something a bit more cheerful, but anyway...