after playing many mobile games (J2ME), I summarised the following points that are common in current mobile games: 1. hard to control. As most mobile phones are not designed for gaming, so the keypad may not be flexible for games especially action games that need a lot of pressing. 2. too long/short. Some games are just too short, there are some games that cost me only several hours to finish, while some are very long, I don't mean the game has a long story, I mean in some games players just repeat the samething, so it becomes boring. 3. bad programming. There a several role-play game, the maps are tile-based, which (I guess) just use the dimension of a grid as the length of character's step, this has an advantage as you can just use a 2D array to represent spirits' position and it's easy to detect whether spirits can walk across grids or not, but this also has disadvantage as usually the grid length is not small enough so the player will see sprites 'teleport', not smooth.