If you played the original Resident Evil 4, you probably remember the rocket launcher. This single-shot weapon can make short work of just about any target - but it comes at a price. Though you can buy the rocket very early on, the chances that you'll have the cash or the inventory space for it are low, and the fact that it can only take out a single enemy means using it in the early game is a poor return on your investment. You wouldn’t use a Master Ball on a Fearow, and you wouldn’t use the rocket launcher on a run-of-the-mill chainsaw guy.
Even though the rocket launcher only has one rocket, that doesn't mean you can only use it once. In the original, the rocket costs 30,000 Pesetas, which is a sizable chunk of change, but you can buy quite a few of them throughout the game. For the sake of comparison, a fully upgrading the Broken Butterfly costs about 450,000Pt. Which would you rather have, a fully modded Magnum you'll have money for, or 15 rocket launchers?
The most common uses for the rocket launcher are the double Garrador fight, the double Gigante fight, and the Verdugo - but you don't actually have to kill that last one. There's a group of cultists you can hit with the rocket in Chapter 3 for a special cutscene, and you can blow a whole in the rubble in the mines with the rocket too. Rockets are valuable, but you'll find quite a few opportunities to use them throughout the original game.
That’s not the case in the remake. The rocket is far more expensive now, and serves a much different purpose. Instead of 30,000Pt, the rocket costs 160,000Pt. The economy is very different in the remake, but suffice to say you're not going to buy multiple rockets throughout the campaign unless you're willing to make some serious sacrifices to all of your other weapons. Its not recommended, nor is it feasible.
This creates an interesting relationship with the rocket launcher. You'll find it in the store practically from the beginning, just like before, but knowing it's probably the only one makes buying it a much more difficult decision. It's the Master Ball problem: you only get one, so you better make it count.
Almost every time I visited the Merchant I considered whether or not it was the right time to buy it. Sometimes it was out of the question because my funds were too low, but every once in awhile I'd count up all my gems and trinkets and try to decide if it was worth selling everything and picking up the rocket.
There were a few times I hit a wall, and nearly pulled the trigger. The double Garrador boss fight did indeed cause a problem for me, and I briefly considered back tracking to the Merchant and picking it up. But each time I got stuck, I decided to push through. If I didn't absolutely need the rocket, I figured it was better to wait until I did.
The trick to it, just like the Master Ball, is that you never will actually need it. The game isn't designed for a rocket launcher moment, and there aren't any bosses that require you to use it. I ended up finally getting it during my final visit with the Merchant ahead of the Saddler showdown. I sold all the gems I'd been hoarding and clicked buy, and the Merchant gave me a cryptic message about the balance of power - one I immediately understood when I walked into the Saddler fight, hit it with a rocket, and instantly ended the final boss fight.
Throughout the entire game, the rocket launcher feels like something powerful to work towards. You skimp and save, delay gratification, a wait for the perfect moment to finally buy the thing you've had your eye on the entire game. But when you actually use it, you realize you've only cheated yourself. You spend so long meticulously filling your Pokedex and traversing the Unknown Dungeon to find Mewtwo, is it really that satisfying to skip the entire battle and just huck the instant-catch ball at it? The rocket launcher is Resident Evil 4's Master Ball. Even though they take a lot of work to get, you might not actually want to use them.