Wouldn't recommend 2chan, probably full of internet slang.
Well, Wikipedia is one option. Or visual novels, but that's a literary style. One more thing is personal blogs, you can maybe search for game reviews written by Japanese bloggers. The term you need to search for here is either the katakana version of review (レビュー), or 感想 (kansou, meaning thoughts, impressions), this is usually how bloggers label their reviews.