The main feature was the ability of the engine to create monsters, put them in map and allow player to slay them in melee. A spawn system was also desired. A single monster to begin with: goblin, obviously. Oh, and the time system went on also (rounds count).
Secondary features were simply more items to play with and the ability of the engine to prevent player to use an item if its character class doesn't allows... i.e. no swords or armors for magic-users.
Every Area (the 64x64 tiles piece of world in which player currently is) has an array of Spawn things. A Spawn is a sort of timer programmed to create and put in map a monster of a kind every X rounds at a certain position. After N creatures spawned it is destroyed. Viewed in these terms, is a very slow paced particle emitter
For example, a pile of garbage can be a spawn point for dire rats or centipedes or other kind of vermins, or a cemetery for zombies. I think this way the Area is more alive, and player doesn't ever know if it's all been cleared or not.
Next version will give some kind of basic AI to goblin and maybe a couple or more of new monsters. I would like to manage the loot also.
Here is a screenshot of a cleric beating a goblin.