So, a game I'm working on takes place in a psychological landscape. However, some of the monsters the player encounters are real creatures within the universe the player character comes from, and some of them are creations of their damaged little mind. So, I needed a way to distinguish between the two, and I'm presenting it for a second opinion.

Basically, the things that are real in the universe the character comes from will perform like a real creature. When damaged, they'll bleed, go into shock and slowly die the way a real living thing does. Their attacks will deal physical damage to the player's body and inflict bleed. When they die, their body remains there and performs like a regular object. This makes these fights seem quite real.

However, the things that are completely fabricated by the player character will not perform like real creatures. When damaged, they just lose a fixed amount of health instead of bleeding. They don't go into shock, and keep functioning perfectly (aside from body damage, they still feel that) right up to the point of death. Their attacks don't deal physical damage, instead dealing fake damage composed of two other status effects (fatigue and pain) that mimics the effects of real damage on the player's body only semi-convincingly, and fake bleed that takes from the stamina and will meters instead of health and thus only mimics the actual effects of bleeding only semi-convincingly. These effects also all go away much faster than real damage heals, and the visual effects of the damage they're supposedly dealing will go away faster still instead of lingering until the damage heals the way regular wound graphics would. Finally, something strange (but different for each one) will happen to the bodies of these creatures that removes them from the game. Dissolving, exploding, catching fire, fading out of existence, vanishing in a flash of light, launching into the sky to never return, so on. Some of these effects (like them catching fire or exploding) will be able to harm the player, although of course with fake damage. This all makes the fights much more surreal, and much less believable.

So, how's that? Is it a good enough distinction that the player can pick up on it when they're not told they're in a psychological landscape, much less that some of the enemies are based on real things their character has encountered and some aren't? Because the distinction needs to be that strong.

For this post I'll refer to the psychological enemies as "fake enemies". I think that the fake enemies would certainly stand out as different types of enemies at some point. I have two questions which depend on your goals:

1. Should the player be able to tell the difference immediately, e.g. if a real and fake enemy stand next to each other?
2. Is it important that the player figures out quickly that the fake enemies are psychological as opposed to literal monsters/supernatural beings? I know that's not your goal, but some players may initially think this because so many games have such things.

You could also use behavioural differences such as:

• Limited emotional/behavioural range.
• Failing to avoid environmental hazards.
• Lack of pain response.
• Real enemies don't see fake enemies, and may even walk through them.
• Fake enemies may appear in areas they couldn't possibly be, e.g. from a previously viewed dead-end.

You could also do visual stuff such as lacking a shadow, bleeding too much/too little, etc.

For this post I'll refer to the psychological enemies as "fake enemies". I think that the fake enemies would certainly stand out as different types of enemies at some point. I have two questions which depend on your goals:

Shoot.

• Should the player be able to tell the difference immediately, e.g. if a real and fake enemy stand next to each other?
• Is it important that the player figures out quickly that the fake enemies are psychological as opposed to literal monsters/supernatural beings? I know that's not your goal, but some players may initially think this because so many games have such things.

1. No, there should be ambiguity. Ideally, they should figure it out only after the fact, when they're done freaking out about the enemy acting nothing like what they're used to. (They'll likely have played at least an hour before running into one.)

2. Nope. As long as they realize they're not the same, that's enough.

You could also use behavioural differences such as:

• Limited emotional/behavioural range.
• Failing to avoid environmental hazards.
• Lack of pain response.
• Real enemies don't see fake enemies, and may even walk through them.
• Fake enemies may appear in areas they couldn't possibly be, e.g. from a previously viewed dead-end.

You could also do visual stuff such as lacking a shadow, bleeding too much/too little, etc.

1. Oh, the "fake" enemies are quite single-minded already. Most of them set out specifically to torment the player in a fresh and exciting way, although some have very distinct and bizarre behaviour patterns that don't involve that, where as "real" ones behave realistically and act in their own self-interests instead of persecuting the player.
2. Oh, that's not an issue with most of them. Environmental hazards are pretty low-key in this game, and these creatures should be able to avoid them just fine. And some, they're outright immune to. (Like weather. Most are completely, 100% totally immune to weather. Even if it's a driving blizzard of glowing blue radioactive snow outside, they're immune.)
3. No, that doesn't fit them very well.
4. "Real" enemies and "fake" enemies don't appear simultaneously. "Fake" enemies only spawn when no "real" enemies are present in the area. (The "area" is the 1x1 kilometre square you are presently in.) And remember, I can easily have it manipulated so "fake" enemies flee or disappear when "real" ones are around so as to make sure they don't cross paths.
5. Already part of it.
6. Some of this is done, some isn't. But the "fake" enemies don't bleed. I thought I said that.

I like the idea.

Maybe their shading could be manipulated a bit as they take damage?

No. See, there's two points to them failing to react to health damage until the moment they die.

1. They're scarier and less predictable that way, as the player can't gauge their health.
2. They begin to resemble conventional video game enemies if they don't react to health damage until they die, things that are obviously not real and might clue the player in to their true nature. Or at least make them more suspicious.