Why Hard Games Feel Great - Extra Credits Gaming

Ever feel like you're getting whiplash in a game? Like you feel like you're moving at a good clip, but then suddenly you're making progress more slowly or the opposite, just killing stuff way too quick. Ever wonder why that is? Well, then buckle up and put your math caps on because we're about to run headlong into the jerk principle. Thanks so much to Cell to Singularity for not being jerks and supporting today's gaming discussion. One of the most important, yet also most overlooked concepts in systems design and game design in general, is the concept of looking at both V and delta V in everything you do. Of course, you might be asking, "What does V and delta V even mean?" Well, to put it simply, it is velocity and change in velocity. And they can be commonly thought of as what the player is experiencing right now and the trajectory of their experience. So, let's jump into a simple example. Let's say it takes a player 5 minutes to get from level 1 to level 2 and 8 minutes to get from level 2 to level 3. This means

that the player's leveling velocity, the speed at which they gain a level, V at level 2 is one level every 8 minutes. But their delta V, or change in velocity, from level 1 to level 2 is plus 3. This seems totally reasonable and it is at this point. But then let's say your game caps out at around level 120. If your delta V remains constant, that means getting from level 119 to 120 will take about 3 hours of real world time. Is that acceptable? I mean, it might be. There might be a game where you hit your final level and want someone to spend 3 hours. But then let's ask ourselves the bigger question. How long would the whole game take? Looking at about 363 hours. Yikes. Now, unless you're making an MMO, that's probably not okay. But simply by setting your delta V to plus 3, that's where you ended up. This often leads to funky kludgy math put in later in development to haul that number down and it's that type of math that often leads to bugs, exploits, strange-feeling gameplay, or

what I call the jerk principle. James thinks that's funny because jerk is the second derivative of velocity, or velocity over time over time. Ha, hilarious. And then I told him, "You know it's funny when you have to explain the joke to everyone but a few dozen physics majors out there." Then he called me a jerk. Look at that, full circle. But the jerk principle is important because like in the real world, it's where you feel the change. Okay. You know how when you're driving with someone and they're accelerating smoothly, you barely feel it. But when they slam on the brakes, ooh, you notice. That's because what you feel is the change in acceleration, not actually acceleration itself. And that is just as true in games. Ever play a game where all of the sudden getting to the next level seems like it's taking forever? Or on the other hand, where leveling up just seems to breeze by? That's often because we're using kludge math to pull the curve back into line. It's often where we're actually changing the math that controls delta the V entirely because we didn't set up a system from the outset that could cover the whole range of our game. If you look at

leveling systems in MMOs, you see this all the time. There's one set of leveling XP {slash} math that covers a certain range, and then it's replaced with a different set of equations once you've gone beyond that. This is clunky. And like in the real world, never feels great if we suddenly massively decelerate you. And you really feel it when the amount of time it occurs in is more compressed. In fact, most of you have probably felt it in time to kill You know that moment where you get a new weapon and it just feels OP because you're mowing through everything. Or when you suddenly feel like you're slapping all the enemies with a wet noodle because they're taking a ton more hits to kill. That's because on the design side, someone changed the delta V and created a bunch of jerk. Or jerks in the case of NPCs, so um jerky jerks? Yeah, let's go with that. This can happen for a lot of reasons. Sometimes you want an area to be prohibitively hard unless you have the right gear, in which case, as a designer, you use high jerk to notify the player that they're not supposed to be there yet until they have the right gear. Or sometimes, it's used to make you feel powerful and give

you something that will just massacre everything where you are in the game currently. But to balance that, they need to make the area immediately following it jump up in difficulty, which leads to the knock-on effect of all future weapons needing to have a bigger delta V from your previous ones. I.e., if all of your monsters get more powerful, future weapons need to be proportionally more powerful to feel like similarly powerful upgrades to earlier weapons, which means a new equation for delta V. Man, that was a mouthful. Okay, specific example time. Imagine you're playing a Souls-like. Oh, sorry, I was doing that. It was kind of fun, actually. Okay, in the area that you're in, enemies have nine hit points and your weapon does three damage, meaning it takes three hits to kill an enemy. In the next area, enemies have 12 hit points. So, to make you feel like you're keeping pace, we have to give you a weapon that deals four damage. Then the same delta V on everything in the area after that. So, enemies would then have 15 hit points, weapon you get deals five. But now, let's say we want to make you feel unstoppable for a bit. So, when you beat the mini-boss of the area, we

give you a weapon that does a whopping 15 points of damage. Heck, yeah. Everything's going down in one hit now. But we eventually have to adjust the math. So, in the following area, the average enemy has 45 hit points and we don't give you a new weapon. So, now you're back to having to hit an enemy like three times to take it down. Then say in the area following that one, the enemies have 60 hit points. Okay, so how much better is the weapon we have to give you here to make you feel like you're getting the kind of improvement you got from the first area to the second one? We have to give you a 20 damage weapon. Or one with a delta V of plus five instead of plus one, putting us on a totally different scale. Of course, that was an oversimplified example, but you still do feel the jerk, right? You were a mortal, you were a god, and then you came crashing back down to Earth. And in doing so, it introduces those risks and danger points that jerk always does. Let's say we didn't match up our XP equations perfectly, and so an enemy in area three gave you enough experience to still be

relevant in area four. Well, now you can just farm those with ease, causing a whole bunch of other pacing problems down the line. And you actually notice this a lot in competitive games. If you've ever had that moment where you face someone with a slightly better gun, or who's a level or two up from you, and then they kill you in like two seconds flat, and then you're all like, "Ah, come on! I DID EVERYTHING RIGHT. I WAS SHOOTING them as much as they were shooting me, and it didn't even feel close." Well, that is either a poorly planned Delta V, or a disjunct point causing jerk. So much of balance comes down to thinking not only about V, but about Delta V. About how whatever you're building affects not just the player's experience in the moment, but also how it fits with what comes before, or how it shapes what comes after. Which means, as a designer, if you're going to change your equations, if you're going to make massive disruptions in your Delta V, that disruption should be on purpose. Otherwise, your players are going to think that you're just being, uh, butt. Okay, real talk though. A game we actually just found that does a really

great job at balancing their Delta V is called Cell to Singularity. And it's a free-to-play idle game that's been filling up the majority of my moments recently. Actually, it's kind of the perfect synergy between everything we love here at Extra Credits and Extra History. The TLDR is you play through the entire development of life on Earth and the vastness of our solar system, like literally everything from cell to singularity. You start in the primary simulation, which spans everything from amino acids to humanoid colonists, to the Stone Age to Martian cities. But then you get to branch out into the Mesozoic Valley simulation, where you can see dinos. Hi dinos. Oh, bye dinos. And the Beyond simulation, which covers our solar system and beyond. Plus, there's even a rotating fourth simulation they have that spans a ton of topics from things like the history of tea to philosophy to the human body and more. I love checking in and seeing what's cooking over there. And with its intuitive gameplay, gorgeous art style, and killer scientific and historical factoids for every unlock along the way, I've been playing this game non-stop for

weeks. And I'm literally playing right now as Jeff and I are writing this read. Look at this. Say hi TO JEFF. I FOUND SOME BUNNIES. Let's make more bunnies. Actually, a quick aside, we got to speak with the developers of Cell to Singularity for a bit and they were just an awesome group of folks who were passionate about science and history who also wanted to make a game that was just so much fun that you can't help but want to play it. Again, very much like what we strive for on this channel, so I was just super happy to send folks their way. You can try out Cell to Singularity for free right here and then be sure to leave it running while you check out our next video here. A legendary thanks to Ahmet Ziya Turk, Angela Valenciana, Arcalite Games, Dominic Valenciana, Ilknur, Easy Coin, Joseph Blame, and Kulyakoy for all of their support on Patreon.