I believe @Nicolas has a number of gamification plugins that are quite helpful 😄
For the second question, you'll want to create or customise an existing theme so that the topic layout is vertical.
Is it possible to include additional metadata into a post? I am looking to have users write game reviews on my site, and include some sections with key information for searching and creating embeds. The more customizable, the better, but I would ultimately want something like:
Nope. You would need to make a plugin. There's no way to add any additional data to the post without writing your own functions to handle the submit action.