Wow, making an RPG is hard. I mean you have to be a master of databases and spreadsheets, just to keep track of everything. I have a list of 250 items, all of which can be customised, lists of monsters, to hit tables, spells, abilities, status effects and all these things have to interact with each other behind the scenes.

How do you keep the game challenging? And fun? If you give the player a +5 sword, will it make him overpowered and the next few levels will be too easy? What about if you give him +5 armour? If you don't drop the right weapon will the player get frustrated and just give up? How do you scale the experience so that the monsters get tougher as the player gets better? Do you base it on the players skill or the players Characters skill? Whoa.

I'm currently playtesting and asking myself these questions, but I definitely know one thing - my next game won't be an RPG!

I think I've figured out a few things -

Monsters strength will be based on the players level when he enters the dungeon. A level 5 character entering the dungeon will encounter level 5 and level 6 monsters.
The player should (on average) gain 1 level per dungeon.
Items will be randomly awarded during the level.
At the end of the level there will be a shop where you can sell unwanted items, buy new items and upgrade existing items.
There will be an element of skill when defending during combat, a correct keypress at the correct time will half the damage.
Attacks during combat will be based on a dice roll + the characters skill with the currently wielded weapon.