It’s more of a controlled randomness though, where the engine tells the zombies, withces, tanks etc which spots they can appear this time and randomize these spots. But for the player it feels like a new experience since you can’t put your trust in that the zombies will be the same place as last time. Which in turn makes the game more scary.

I think World of Warcraft has a pattern breaker coded into it so that you can only miss a limited number of times in a row because they know the calibre of their playerbase ;)

A) No randomness equals pure strategy. This is good if there is sufficient challenge, depth, and balance (Chess, Go).

B) Pure randomness equals an easy, but challenge-less game. This is good for teaching game structure or for being a moderately (and sometimes addictive) time waster (Snakes-and-Ladders, War).

C) Some randomness can be good or bad. The goal is to have controlled randomness. Allow the randomness to provide variation and temporary inequality while the depth and strategy make up the majority of the game. This is a difficult balancing act: too much randomness and there is a feeling of no control or frustration caused by game breaking chance, not enough randomness and the game will always play the same way or feel stale and one-sided.

The key to using randomness in a game’s design is to figure out what needs to be random, and how random it needs to be to add spice and friction to the gameplay.

A. Chess, from your first example, is a game of fierce competition. The better strategic mind wins every time. Sure, you can beat Kasparov but it will take lots of potential and years of training. People enjoy that kind of challenge.

B. Total randomness gives you the feeling of lost control. Think about people doing the lottery every week. They basically pool their money and give the whole sum as a gift to the lucky winner. Who has no other merit than his luck. Some people enjoy that. Or even hearing those stories.

C. Some randomness usually gives you a feeling of varied circumstances and conditions or more simply uncertainty. “Usually when I do this I’m gonna win but sometimes it doesn’t work out.” As you said it is usually used to lessen the advantage of “better players” or make the game more complex and varied. Most people like that. But the game still requires skill so there’s a possibility that people who like the B games can’t be bothered. And potentially people who like the A games can’t be bothered either because the randomness comes in the way of their pursuit of total mastery over the game.

There’s of course lots of more about this, but my point is that it is mostly up to personal gaming preferences.

Just my 2 cents.