I’m very sorry, but I still have a few more things to write about Castlevania. You may slam your computer angrily, if it makes you feel better.
Specifically, I want to mention what might be the most interesting items in the game: The weapon multipliers. The concept of a power-up was in itself nothing particularly new by the time Castlevania rolled around; that mechanic was deeply entrenched in the medium by that point. What made Castlevania’s multiplier power-ups interesting, however, is that they had no value on their own but rather deepened the complexity and utility of other weapons.
The double and triple multipliers allow Simon Belmont to have two or three subweapons on-screen simultaneously. By default, he can only chuck one item at a time, which makes them somewhat useful but rarely superior to simply whipping the crap out of things. With a multiplier, however, certain subweapons become incredibly valuable, especially in specific situations (read: Facing off against bosses). Holy water becomes overlapping curtains of blue fire that can stun most foes. Boomerangs fill the screen. Even the miserable dagger is somewhat useful with a multiplier! The only weapon that doesn’t benefit from it is the stopwatch, because its function is fairly binary and absolute.
The thing that makes multipliers interesting is that, with only a few exceptions, you only get them by attacking foes with a subweapon. You have to use your weapons to power them up (an idea the SaGa series would take to heart a few years later). Because you have to spend hearts — a sort of collectible currency — in order to use subweapons, the multipliers create a value proposition. Do you expend the hearts necessary to upgrade a weapon, potentially leaving yourself with a shortage of hearts to spend once the multipliers drop? Or do you take a more frugal approach, conserving ammunition but potentially leaving yourself with insufficient firepower to win the day? It’s an interesting question, especially in the run-up to certain bosses where you have the opportunity to collect a very finite number of hearts.
The multipliers concept isn’t without its flaws, though. It suffers the same drawback as Gradius‘ power-up system, though to a lesser degree: Once you die, you lose your cool weapon and its added firepower, leaving you potentially screwed in certain situations (this becomes especially troublesome in Stage 12 and the crummy arsenal it offers as you fight your way back to The Creature and Igor). On the other hand, you lose multipliers simply by collecting an alternate weapon, so you could argue that the designers wove this power-reset mechanic into the fabric of the game from the beginning. In any case, multiplayers remain one of the most creative and unique concepts in Castlevania. Well done, video game.