Anything that I give a review on will be a rating out of 5. Allow me to elaborate on what my view on the Ratings are.
Must Buy:
A Game with a solid rating of 5 out of 5 is a game I feel should be owned by anyone and everyone. I am of the opinion that it is that good it would be a lasting game and has more than one playthrough.
Rent aka Try before you buy:
This is the view where I would say is split. If I have viewed something as a 4/5 it means that it is something that should be played by everyone but may not be something you want to buy straight away or that it is only worth the one play through. 3/5 is what I would definitely say to rent the game before you buy it.
Avoid at all costs:
I think this title says it all really. My thoughts would be to avoid the game has it wasn't very good at all. 2/5 is a little better than 1/5 but in my opinion still something that should be avoided.