- Famous examples: Final Fantasy, Chrono Trigger, Dragon Quest
- Linear story line: there's some exploration available but it's like reading a book; it's designed to move the plot and get you to the next place.
- Linear weapon system: you only use 1 sword until you pick up the next improved sword, and then you'll never use the old sword again because it's inferior in stats.
- Turn-based fighting: uses menu selection to choose things like Attack, Use Item, Heal, etc.
- Famous examples: Oblivion, Fallout, Fable
- Freedom: completely open world game play. Everything is defined by the user's decisions, and you choose to accept/decline any missions or meet any characters.
- Inventory-based weapon system (crafting): when you get 1 sword, you can keep upgrading it by adding accessories (like power-up gems) or using it to create an entirely new sword
- Real-time fighting: more action (involves aiming and firing/attacking) with a percentage hit rate
As a side note, there do exist hybrid RPGs such as Mass Effect, where the game is more plot-oriented (you alway play the same character in the story), but you can choose how they develop and what class they become. Feeling smarter already? As usual the Internet and Wikipedia have already dominated this subject thoroughly, so no need to take my word for it!
We have plenty of similarities... odd-shaped ears, form fitting outfits, and unpleasant expressions.