Beyond the upgraded Skeleton Knight on the upper spur of the catacombs route, Trevor and pal enter Castlevania proper: The lowest foundations of the castle, a cavernous space over a subterranean lake. Since this is the path that sends you through the greatest amount of castle territory possible, we can consider this the “prime” route through the game. It’s also probably the easier of the two, if only for the fact that this block spans a mere two sections, making it the shortest block in the game… which isn’t to say it’s particularly toothless.
Alucard comes in very handy for specific points of this stage and in fact all the levels ahead — not because he’s a particularly effective fighter, but because you’ll encounter lots of environmental hazards and really annoying trap situations that go a lot more easily if he can simply glide on past.
Block 6 takes design cues from Stage 10 of the original Castlevania, featuring plenty of moving platforms that convey you across water as you’re beset by Fish Men and bats. And, as in Stage 10, once you reach the far side you need to double back via staircase to the level above. Block 6-02 even has the bit where you have to duck while riding a platform to avoid being scraped off by low-hanging stalactites. In fact, you could reasonably assume this level is meant to compromise the same space as Stage 10 of the first game, a notion given some weight by the choice of boss waiting for you at the end.
Unlike this sequence of the original Castlevania, though, this contains a few nasty new traps, the worst being the mummies that materialize in at the end of Block 6-01 to trap you on completely flat ground. It’s insanely difficult to make your way past them as Trevor without taking a few hits — though of course Alucard can flutter right over them, though in doing so you’ll miss out on the Axe that makes the difficulty level of Block 6-02 considerably less crushing.
Spikes and low ceilings play some nasty tricks on you in Block 6-02. If you’re like me, you tend to jump to safety from moving platforms or hop down to lower levels instead of taking the stairs, but there are several spots at which those behaviors will be instantly fatal. Try to jump to solid ground here and Trevor will impale his skull on the spikes lining the ceiling; clearly the developers want you to take the trickier approach of walking across the two types of ground, which requires precise timing to prevent you from plummeting to your doom. Beyond here is a point where a short stair path takes you down to the lower level, and if you try jumping you’ll hit your head and drop into a pit. There are no shortcuts here — unless you take along Alucard, of course.
At the end of this route is Frankenstein’s Creature, a few centuries before Victor Frankenstein lived. This battle is essentially the same as the one along Sypha’s route, with a few small differences. For one, you can’t as easily rely on “safe” ground above and to the right since you have to climb slowly via stairs rather than leaping. Secondly, his stomp attack now causes more masonry to fall on you. And, finally, you don’t have Sypha to take him down at double-time with her fire spell. Alucard is more or less useless in this fight, so it’s really down to Trevor and, if you’re lucky, a decent weapon. Thankfully, the stage is pretty brief to play through again if you die horribly, which makes it the less demanding path into the castle compared to the alternate version of Block 6.