A.K.A. Another (Probably Last) Binding of Isaac Themed Post. For Reals this Time, I Hope
A "Content Gate" is simultaneously sort of a familiar yet foreign term. It's not a term that gets bandied about a whole lot, but at the same time the vast majority of games use content gates, because without content gates most times things become a large mess.
Content gates can take many forms, perhaps the most obvious and one of the most implemented is the skill gate. For this one you need look no further then the first Super Mario Brothers. You couldn't just go straight to world 8-4 as soon as you put in the cartridge -- you could certainly get there faster if you knew where the warp zones were -- you had to beat levels that increased in difficulty as you moved forward. From the relatively sparse and fairly non-threatening world 1-1 to the difficult jumps and endless Hammer Bros. of world 8 in general. The skill gate is basically the difficulty curve that ensures a challenge throughout the game, as well as making sure that the end is a reward for those willing to invest the time and effort.
Skill gates don't only apply to the forward thrust of a story, in many cases you can only get unlocks or the chance to purchase unlocks once you get to certain stages or points in the narrative. Some games like Darksiders and God of War II give you a taste of the fully powered (or at least highly empowered) character off the start, only to take it away as incentive for the player to regain the former glory of the character. The point is that in games with large power suites earning them requires work (or cheating), you don't just get handed everything on a silver platter.
Of course this blends well into the second type of content gate I'm going to discuss: the currency gate. This one is used less often to stop the player from moving forward -- although it's not too surprising to see it used as a content gate as well in some cases -- but more often used to hold advantages from the player. Want better weapons, or more skills? Then you need to grind money, or experience, or something else. Technically an RPG could be considered more of a currency gate depending, because there's nothing to stop someone to grinding to the highest level in the first area in most cases. Sure, you don't have the best weapons or armour, but the level itself gives you so much power that it hardly makes a difference.
Currency gates (or perhaps grind gates would be a better name?) are often cited as somewhat frustrating because they can stall forward momentum. I find personally that when they are well executed in allowing the player to get more by playing better or smarter that it helps mitigate a lot of the problem, although it doesn't eliminate it entirely. Often it takes a combination of various factors to control the pitch well enough to keep the experience both fair and fun.
So, where does the Binding of Isaac come in to all of this? Well, there's a third type of gate, and it's one that I'm not a huge fan of: this kind of content gate is the luck gate, and it's something that recently hit BoI hard in one particular segment. One of the last content updates added a brand new final level, but it's one that comes with a catch: you need one specific item to actually get there. It's not just a matter of being good enough to beat the pseudo-final boss, you have to have a randomly generated item to get to the true final area.
There has been a promised re-balancing announced, but at the moment I cannot relate just how unbelievably frustrating it is to play a game where it feels like extra content has been given almost as more of a punishment then a reward. It's not about the achievements, or bragging rights, it's about playing the game the way that it's arguably intended to be played, but then not being able to because the RNG hates you. It's not a good feeling, and it's one that, in my mind at least, really solidifies the luck gate as the worst kind of content gate.
Are there games without content gates? I feel tempted to name Minecraft as one, because it just drops you into a world and tells you to 'go', but even there you build up to certain levels of competence and convenience. A game without content gates would certainly be a sight to see, but I'm wondering if it's because it would only be an amazing train-wreck.