Halo 2 does it by giving the player a combination of enemy strength and intelligence to deal with. (andymerrill.com)
Instead of the JRPG thing where you load into a pocket dimension after bumping into an enemy, if you see an enemy in a dungeon, you approach and fight normally, which improves the flow of dungeon - crawling, makes it easier to gauge enemy strength, and makes exploration tense. (pcgamer.com)
When starting up a new game, you can tinker with the settings for enemy strength, the number of battles, health item frequency, and the required combo level to generate special moves. (thekoalition.com)