Hello, thanks, I can't really answer that question, because it all depends on the very child. Basically there are some rules of the game, that should be quite suitable for everyone. Kids may have an easier alternative, and better thinkers (it's a logical game) may choose the rules of a greater difficulty. So probably no, I do not "really" need variations on rules. Btw. I can't use "children", because then the text doesn't fit into some web elements, i.e. for technical reasons.
As to "Even children can handle the simple rules, and they love the cartoon avatars, too." - I used "simple rules" in the previous sentence, so wouldn't probably want to repeat that. Also the sentence
Even kids can handle that, and they love the cartoon avatars, too"is trying to say, that the children will be happy with both "simple rules" and "simple controls", which comes from the previous sentence. I see you put commas before "and" and "too", I used that, thanks.
Somehow the sentence
"Variations on the basic rules make the game suitable for them as well as for the experienced players and adults." sounds a bit weird to me, just do not seem to find out why and what is the better way. But it must be short, because of the technical limitation, that I have mentioned. If it is syntactically correct, please do not make yourself big heads with that at this moment. However, advices are welcome. Thanks again.