There was a mobile (android, ios) card game that I really liked playing. Last year, the game was removed from the store and noone were able to play it. The company is still up.
That game had a really original Rock-Paper-Scissor battle system. Cards with rock attribute could beat cards with scissor attribute, etc.
Each card had one or more skills to change the board situation slightly so that you can beat the opposing card.
(For instance, A Paper could turn to a Rock to beat opposing Scissor, if it had the skill ready.)
(As another example, a card could turn all opposing forces to Papers.)
The game had a rare damage mechanic where you lose points according to the cards that lost the battle for you.
The game also had a card crafting mechanic where you could create your own card with selected skills.
Is it legal to copy above mentioned mechanics with a customized art, as a new game? How can I check the laws regarding to that situation? Is there a way to find reliable lawyers in that area?
Note: I am asking this as a new question because the game is not even in the stores right now. It should make a legal difference in my opinion.
Thanks in advance.