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Another reviewer gave the game a B + grade , saying that it is a " little gem " , justifying by noting that though he did feel it is a rip-off of Phoenix or Demon Attack , he believed it is fun and employs a good colour scheme .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None