shortcodes and cutsom fields qustions

I own anime site and I have pretty much of anime. I want to create list (with plugin) of anime which falls under some genre. I thought of doing this by adding genres in custom field. So if I stick with this way:
1. How to add multiple values under one meta key so that key considered array of genres?
2. I want to have shortcode with parameter, ( like [genres g=comedy]) and I need value of this g (in this example is comedy) to be passed to variable, that later will be used in query. Is this possible to do?
3. If I just add in query meta_key=genres&meta_value=comedy (genres is the name of custom field and so is key) it will only find post that have only comedy as value, and won’t find post if it have key like comedy, drama, action and so on. I think I typed values in value of key wrong or i did something other wrong. I need post to be found even if it have more then one value
Can anyone help me and answer on questions and show what i did wrong