Making your game general

ITT we discuss how to collaboratively design our games.

There are two ways of adding difficulty:
A. Invisible trap located in random location in a Room.
B. Invisible trap located in random location in a Room, but it adds small holes in the floor where the trap is located.
Players can't adapt to A, but with B the player will eventually learn to stay away from holes in the floor = avoiding the trap.
A is unfair game design because it denies the player opportunity to adjust to gameworld. Designers that add type A content that can't be adjusted to are adding "opaque difficulty".

Adding a invisible time-switch that does bad thing X to player when he reaches specific time(or enters a room) is type A design.