User blog comment:Takeshi64/Hazard? Enemy?/@comment-3060206-20120511051509
Nitrome games are each different, and because of the variety in their games, it's really difficult to have a set definition of characteristics that strictly defines an enemy or hazard. There will always be exception to what we define as an enemy or hazard, so our best bet is to use our own sense and hope that the rest of the community agrees.
Basically, my perspective of all this starts with the definition of interactive objects. In terms of a Nitrome game, it's anything that responds to the main character or the player, usually by direct contact. You click on a help sign, it gives you what Rockitty is thinking. With hot tiles, the ice cream characters blow ice all over them, and the ice melts. Of course, it's all objects within the game you play. So clicking on an advertisement outside the game module is of course an invalid point.
Likewise, we move on to hazards. Hazards are a more specific type of interactive object. If the main character touches spikes, it responds by losing health or a loss for the player. A hazard is basically any interactive object that is dangerous to the player. Usually, this means losing the game or losing a portion of health which in turn can lead to losing the game. Sometimes, there are objects that are potentially dangerous and one could argue that they are hazards even if they don't cause the player to lose health directly. An example of this is wind from Frost Bite 2. When wind directly makes contact with the eskimo, she doesn't lose any health immediately. Rather, the wind is capable of pushing her into other hazards, such as spikes, or other enemies. This is what players can perceive as "dangerous" as the eskimo is more likely to fall into more dangerous areas rather than go where the player commands her to go.
And now for enemies. Enemies are a type of hazards. All enemies are hazardous, but not all hazards are enemies. Normally, when the main character makes contact with them, it causes them to lose health or lose the game. But enemies also, according to the Encarta dictionary I just pulled up on Word (:P), "[seek] to harm somebody or something". This is typically where things start getting into the "I just know that's an enemy/hazard!" and there's no specific characteristic to completely define that.
The characteristics of an enemy are usually defined per game. For example, in Square Meal, enemies are the ones that the troll spits blocks out at and eats them. They are unable to eat objects such as stand-on spikes. These are still dangerous, but they're not exactly out to get our main character. That's what defines hazards and enemies in Square Meal: you eat enemies, but not hazards.
In most cases, enemies will have some form of an attack, be it shooting bullets at the main character, chasing them down or just walking back and forth, getting in the way. Usually they are defined by facial features, as enemies are considered "living", however, Nitrome puts faces on a lot of their objects, and the subject becomes arguable once more.
And we always have to worry about the exceptions. Sleeping Monsters in Magneboy don't attempt to hurt our protagonist, nor do they actually hurt them. Yet they are still considered enemies. Some of what we call "enemies" don't have faces (for instance, Silly Sausage), nor do they move (again, we can use "Sleeping Monsters" as an example"). Sometimes it is just based on our own tuition. We can argue out definitions for this some time if you'd like, but I'd say that having strict definitions between an enemy and a hazard are real difficult, and this is why the categorization for this can be difficult to understand from a logical point of view.