I've been thinking a little bit about ritualism in games--the repetition of a set of actions for symbolism or meaning that, if not "written" into it from the beginning, is ascribed to it as it is performed again and again. Rituals are performed, and so ritualism defines the doing of something, not aspects of the environment (although rituals are often performed in certain environments). So when I say "ritualism" I don't mean "the fact that all the Mega Man games look the same," but I do mean "the fact that you always have to go through a boss corridor in Mega Man before you get to the actual boss."
The boss corridor is actually a pretty interesting example: in the original Mega Man for Famicom Disk System, the hall was a matter of necessity, so that the game's boss data could load. On a cartridge, that wasn't necessary, but the corridors in that and all subsequent Mega Man games were kept. It's something that could easily have been excised, but having an empty corridor before a boss mentally preps the player for what's coming next, as well as creating a feeling of tension. Of course, there's nothing dangerous about an empty hallway, but it becomes imbued with that "oh shit, here we go" quality from dozens and dozens of hallways before dozens and dozens of Robot Masters. (I also find it interesting that certain players, out of habit, do things like make sure they jump into a Robot Master room instead of just walking in.)
On the topic of hallways, the between-area corridors of Symphony of the Night and other Castlevania games are similar, although those read more like signifiers to me (the same way the flag-raising at the end of a Mario level is signifying the end in a mechanical fashion) rather than rituals. The player can experience them at any point or order due to the nonlinear layouts of the levels, so they only hold significance in that they tell you you're going to a different area. Nevertheless, a lot of ritualism in games takes place in breaks from the gameplay, occurring in space between actions of player progression.
A way more overt example of this is the Vinculum Gate from killer7. In the video below, you can see the general structure and recurring elements of it: the Gatekeeper (who gives you access to the Vinculum Gate in return for Soul Shells), the stairway, the Colosseum, and the encounter with Kess Bloodysunday...
...all of which are meant to embellish the act of fighting one monster as practice for when they show up in the rest of the game. It's a lot of effort to go through for the sake of it; they could simply have added a tutorial or something when you encountered the monster in the actual game, rather than sequestering it in a separate area altogether. But because this is repeated so often in the game and areas like the Colosseum take on this ritualistic gravity, they create a huge impact on the player when you progress to the end of the game and encounter them, suddenly and without warning, in entirely different contexts.
Although it's not always an action that the player themself performs, Suda51 manages to work in ritualistic, repeated speeches into seemingly all of his games. No More Heroes has the player listening to a cell phone call before each boss--personally, through the Wiimote, instead of just through the television speakers--that ends each time with the phrase "step into the Garden of Madness." Flower, Sun and Rain takes this to an absurd extreme: the main character, Sumio Mondo, actually launches into a long, involved, dramatic speech every time he attempts to solve a puzzle.
Incidentally, I find it interesting that a series like Dragon Quest, for all its traditionalism in terms of story, mechanics, environment etc., doesn't actually seem to contain a whole lot of ritualism. There aren't that many actions that are carried over from one game to the next and imbued with meaning. In every game you can attack enemies or use magic, but because those are purely gameplay techniques, the feeling is purely mechanical. In the first game you had to use the Staff of Rain and the Stones of Sunlight to make the Rainbow Drop in order to make the Rainbow Bridge, which was pretty interesting and a ritual in and of itself, but it's only performed once and doesn't carry over into any of the other games. In that sense, a fantastic or magical setting doesn't necessarily ensure that there's going to be any "rituals" in that sense.
At the same time, though, La-Mulana loves ritualism, which is pretty appropriate given the emphasis on ancient ceremonies and spirituality throughout the game. The use of Ankh Jewels and Ankhs to summon the Guardians rather than having them appear automatically is the major example here, although it doubles as a mechanism to make sure the player is fully prepared before a possible boss fight. In that sense, it serves the same purpose as the boss corridors do before a Robot Master. If there is a difference, it's that La-Mulana ties it into a song called Requiem to really hammer it home.