The difficulty of the game is a rather complicated concept. You can smash them for absolute difficulty and relative difficulty (felt).
Absolute difficulty refers to the things you have directly affected as a game designer. This can be the strength of your opponents in FPS games, the advantage of raw materials in a strategy game, or the skill of opponents and the parameters of vehicles in the racing game.
The relative difficulty is something that your influence is very limited, because this concept includes the skills of the player and his experience. It is obvious that a player who has a lot of experience in FPS games will fare much better in this type of games. For this reason, his feelings about the difficulty of the game will be different than the novice. Also, the player who has already played your game will be better advised, because he has already had to know the rules governing it.
In the case of single-player games, ruthless game play typically should gradually increase with czasemaby to compensate for increasing player skills. The first encounter with a new type of opponent can be a big challenge for the player. Over time, however, will learn to fight with him effectively, so the difficulty to feel this element of the game is going to diminish.
In the event that our game assumes a certain amount of levels that a player must defeat, it is worth rethinking how the optimal difficulty of the game should look like in this case. Beginning levels should be easy and gradually become more difficult. After completing the level and starting the next difficulty should fall, however, should be higher than at the beginning of the previous level.
How can it look in the game? The player at the end of the level gains a skill that allows you to overcome enemies more easily, but during the game encounters stronger enemies. Such a level arrangement makes the player can feel his new power that has become actually powerful.