'A game that you'll enjoy' is all about relative clauses.
Producing elegant Relative Clauses is a very rewarding goal (and achievement!) in anyone's second language ... assuming the language has such a feature, as English magnificently does of course.
We hope than honing and choosing these will be 'a game that you'll enjoy'!
Answer 2 is wrong because 'these' (while indeed referring back) is not a true Relative word, and the comma on the join between two main clauses does not offer substantial enough punctuation (though as with many more such subtle points, you may freely come across poor examples 'out there' from native writers who ideally should have known better).
Answer 4 makes sense, but the clash of register between 'of whom' (formally correct) and 'loads' (very informal) undermines the supposedly solemn overall disciplinary effect of the passage.
You would need to avoid slipping into 'many / several / most / some of WHOM ... ', which would tend to suggest that the clients were themselves in some way the fault of the staff!