Game designer of Mega Man
Kitamura: Going through all those games taught me something important, though. I started to think that if I focused on more detailed, intricate enemy behavior and placement, then I could probably achieve a better difficulty balance than what action games had offered so far.
Ariga: I think that attitude become one of the key elements of the Mega Man series.
Kitamura: Also, two of my personal goals for Mega Man were to create a game where all the stages could be cleared in an hour, and to make something that players would want to come back to again and again. To that end, I actually calculated the total number of stages by measuring Mega Man’s walking speed and seeing how long it would take to get through each stage. I then split that up so that the first half of the game would be the robot master stages, and the second would be the Wily stages.
Ariga: Whoa! You really did that?
Kitamura: I also created some rules for myself about enemy placement and design.
#1: Single, weak little enemies would appear in "waves" of 3 or 4 individuals (and to the extent possible, I’d avoid mixing up multiple enemies);
#2: they would all use the same attacks;
#3: I would use differences in terrain and enemy placement to adjust the difficulty of a given section;
#4: The difficulty of each enemy in the wave would gradually rise, but the last enemy to appear would be easier.
Kitamura: Making the last enemy encounter in the wave easier was a key idea. It leaves the player with a softer impression of the game’s difficulty. I think the reason that people don’t replay games—even good ones—is that when they remember playing the game, their minds go back to the extremely difficult parts and enemies, and then replaying the game starts to seem like tedious work. I wanted the player to feel like he was improving at the game too, and that was another reason to make that last enemy easier, I think.
These weren’t my only "tricks" for how to get more replayability, but they were some of the big ones.
Players like little secrets