well of course, you would consider the type of game play too, like does the game have battle system, does the game have character development, does the game have character interaction? these are the things that make up true rpgs
Actually, I disagree. Some of the best RPG's have no combat whatsoever. I'm referring to "Sims", IRC games where people simply chat away, acting out a role, and there are no rules, other than to "be reasonable". So if you pull out your phaser and shoot a Cardassian, the people simming with you wouldn't mind. You would accomplish that simply by typing:
LtJG_Spuzzum> ::sets his phaser to kill and burns a hole through one of the Cardassians:: Eat this!
No mechanics, no rules, and most importantly, no battle system! =)
The following wouldn't be allowed though, because it is almost completely impossible:
LtJG_Spuzzum> ::whips out his phaser and kills all ten Cardassians before they even knew what hit them:: Pitiful Cardassian fools! I am your GOD!
Of course, since most of these "sims" are regulated by moderators (who usually are the CO of the ship, and they guide you through the adventure), you can be assured that if you do something that's relatively unlikely, they'll whisper something to you to change that to something more likely.
Though, the end goal, of course, is to have fun!