IANAL, this is not legal advice, gamedev.SE is not a good site for legal Q&A.
You may have noticed that most promotional material either avoids mentioning competitors, or avoids mentioning them by name.
Example (Colgate):
"Tastes better than the leading competitor"
I believe this issue is covered on the Wikipedia article Comparative Advertising. While it's perfectly okay in most jurisdictions, usually there are strict standards on how factual or truthful the comparison is, and it must not be misleading. Of course this can be up to interpretation, so in order to avoid legal liability, most companies just avoid directly naming the comparison, even if it's blatantly obvious. Your competitors could have many reasons to stop you from mentioning them too, for example to avoid being associated with your product, or to control the image of their own product.
I know that sometimes it's very convenient to describe your product in terms of other products; "it's like Minecraft with an Angry Birds vibe and a Starcraft-esque lore!" your elevator pitch might go. Professionalism issues aside, you can try mentioning genres and game design buzzwords instead. Examples include sandbox, persistent world, action role-playing.