it's already mentioned that only valid arguements will be passed

no, that's not at all the solution to that problem... ;)

The main point here is actually that the initial design of the class is flawed. I hacked it (which is bad, yes) because this should have been implemented in the class in the first place.

In the context of the kata, it cannot be because there isn't much left to do on the user's side, but the overall design isn't really good. Let's go even further, the proper design should be something like what is in the fork (but implemented properly on the Game class, ofc...)

OK. The translation was updated by someone and the name "revrot" was changed to "rev_rot". Change the name of your function to "rev_rot' as said in the initial "Solution". If necessary "Reset" the page.

I am not sure to understand your post.
The kata asks for writing "horizontal_mirror", "vertical_mirror", "oper" nothing else and these functions are tested through "oper" function as can be seen in "Sample tests"; everybody can manage all that as he wants.

duplicate issue above

Same issue in javascript ^^

Fixed in Ruby.

Already raised as an issue.

Fixed.

Did you read the random test cases? Python tests the 4 functions.

Not sure there is still an issue here. I think the idea of the Kata is good as @kingcobra has explained.