What sets aside a really good RPG from a run-of-the–mill point-and-click adventure are the battles (well, unless you count the insult sword fighting scene in the Secret of Monkey Island series at http://monkeyisland.wikia.com/wiki/Insult_Sword_Fighting).

Battles can take many forms, from real-time, hack-and-slash, nonstop action to the more strategic turn-based battle systems. Each appeals to a different audience and dramatically alters how your game is perceived. In many cases, the battles (apart from the story) will make up the heart and soul of your game; if you get this wrong, it's a quick one way - try to uninstall purgatory.

No matter which path you choose, the enemies that the player will face have to be challenging at all times. This doesn't mean they should level up at the same time as the player (in some titles, there is a flat progression between the player and his or her enemies; avoid this at all cost as it will quickly become boring), but then they should challenge...