Question: Can giving someone lives for a game like Candy Crush with good intention be considered a good deed?
Answer: You have to consider if it really does good. E.g. Does it support the spiritual life or create more worldly indulgence? Some become better persons through the game through training patience and such. For some, it simply kills time, thus wasting life itself, distracting the person from more important matters like responsibilities at hand.
Question: Yes, it is arguable. It helps keep the mind active but may cause addiction… The karma created seems complex?
Answer: Which is why you have to consider on a case by case basis! Good intentions without good judgement becomes compassion without wisdom. Now that you know, it is better to be more discerning. Good intentions does create some good karma, but those that lead to good results surely create even more!