Castlevania: Circle of the Moon -- Part 2: Fun Is Fundamental
I think part of what sets Castlevania: Circle of the Moon apart as an unexpectedly powerful example of the fusion of genres and design sensibilities that the series is known for being... despite this game being an "off-brand" example as such, despite being developed in-house by Konami... by another team not typically known for before and afterwards... is the fact that Circle of the Moon takes all the usual set pieces we now take for granted as they were so compellingly codified and unified in Castlevania: Symphony of the Night... but prioritizes them all for the sake of fun.
That is, first and foremost, Nathan is a capable and athletic player character... and a bare minimum of time is spent adding to his basic movement capabilities. It might sound silly, but in many Castlevania games under Koji Igarashi's guidance... you have to UNLOCK the ability to slide. The ability to double-jump is fiercely guarded until at least the midgame (granted, the earlier end of the midgame, but certainly not very early on) to more bizarre choices that one might be willing to sweep under the rug, but "abilities" like being able to get hearts from candlesticks or see how much damage you're doing with every attack... or even the NAME of your enemies as you attack them.
The only things I really have to tip my head to Symphony over Circle is the fact that Alucard walks at a brisk enough pace that he doesn't need to unlock a dash, and he has a pretty indispensible "backdash" movement option from the get-go that's a staple of the series in the so-called "Igavania" games. Otherwise, I'd say they're different spins on the same strong forumula, but Koji Igarashi prefers to drip-feed you even seemingly vital game functions.
I'd only say that withholding the dash and double jump from Nathan actually make "sense" (even if initially it might not seem that way), because suddenly boosting your ability to move quickly along either axis, which has nontrivial influence on even basic combat. (Notice how many needless hits I took from the second Earth Demon once I got the Dash Boots compared to the first one.)
I think if anything, Igarashi wanted to mete these things out as fairly organic improvements on your ability to explore your environment, thus gating off certain parts of the castle (as will necessarily be the case by virtue of the genre) instead of... weird... arbitrary things like stone blocks... and wood boxes... and... whatever that iron maiden-looking thing is we see in this very episode! Circle of the Moon wants you to have these abilities as part of your basic repertoire, even if that means it has to come up with some slightly nonsensical and limited-purpose means to impede progress.
This then frees up a lot of emphasis on making Nathan stronger additively rather than giving him the "expected" tools of a self-respecting action game at a deliberately slowed pace. Then you can revel in the addition of the next DSS card and seeing what happens when you use all the new combinations it provides! You don't even NEED them, so you're not particularly punished if you're not blessed by the random number tarot goddess (you almost certainly won't get anything even approaching a respectable, much less FULL set), but you feel SO empowered when she does indeed smile rather than relieved that the designer god has deigned to give you that crucial tool that's been taunting you all game so far.
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Part 2:
Oh, wait, what? No! No double jumps here! Why would you even assume such a thing! I'm sure we'll never see that, 'cause we JUST got the ability to move at a non-crawling pace that it's evident from the very first descending shaft of platforms isn't properly suited to actual... meaningful and controlled platforming. (Which is why the whole game before the Dash Boots appeared was primarily about descent and horizontal movements.)
What follows is a deceptively open area full of places to just get used to running around and whipping small, mostly one-hit enemies and mobility-challenged multi-hit ones, which incidentally walls off progress subtly with hints that you've just scratched the surface of how Nathan will be moving later.
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Boss: Cerberus
I... can't totally put my finger on it, but this guy... seems... a little familiar. Not OVERLY so, but after I boldly claimed that all the visual assets were totally original... but I feel like this is at least strongly inspired by ...not the Cerberus from Symphony of the Night (which looked markedly different), but... maybe a weird sort of self-sanctioned sprite edit of the very FIRST enemy you find in Symphony, the Warg? It's almost like putting one Warg head behind another Warg to give the illusion of a more complex creature.
...okay... fine... I was lying... there IS a double jump here. I'm SORRY! (I'm not.)
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Now we're free to expand our playground and with it, the promise of both new baddies and goodies alike!