Last Updated: October 12, 2012
Actually it's not as black and white as that sounds. I'm just going to continually update this initial post with problems that occur in most mods that we see, why they happen, and how an individual can fix them.
=Way Too Hard=
So anyone who's played a mod here will notice that some of the mods we see are just absurd in difficulty. Even though we want to see challenging mods out there, these tend to not present any real challenge, but instead are chalk full of fake difficulty. Fake difficulty is when something in a game is hard on the player, but is not their fault. Whether it's 100% exact presicion that's expected or things that pop up and attack the player before they can even react, it's all bad and super frequent here. A proper challenge needs to be presented to the player before they need to tackle it. They need to see what an enemy can do before they are forced to attack it, or see that an object will hurt them before being thrown at it. New things must be presented in an enviornment where the player can learn how to approach them without consequence, before being presented as a challenge.
Another aspect of fake difficulty super common here, is throwing a shit ton of high HP enemies at the player at once. You can only handle so much as a player, and if 15 enemies are there at once, they should only take 1-2 hits to kill, or you should have a strategic advantage over them. If it's 8 Guadi throwing swords at you, then the modder should have made them either easy to kill, or given you cover so you have the ability to avoid taking damage.
Also on this list is save points being misplaced. If you know something is going to be hard on the player, put your save point BEFORE it. If you have learned that the map they're running through always kills players before the end of it, put a save room somewhere in the middle. It's alright to have challenging things, but if you know something will likely kill a player they're first time around, you should A) see if it's fakely difficult and B) put a save point in the area.
This also happens with traps. As a general rule, putting traps that instantly kill the player because they didn't make the game are bad. If only YOU know how to do something, and you EXPECT the player to do it, this is a problem. Fix it.
No health available is also an issue. Cave Story was never afraid to give you health at any point really. Hell doesn't count as it was designed to be fake difficult, but you can't ask a player to go too long without taking damage.
These things happen alot, and they happen because they're the easiest pitfalls to fall into for new game makers. It's easy to justify designing impossible tasks or unfair ones by saying "it's supposed to be hard". This needs to be fixed by carefully planning things out. Don't just make a stage and throw things at it later, get some paper and draw it. Decide where enemies go as you build, not after. Ask yourself if that's fair or reasonable. If your player has enough resources. If they make sense. Approach things in this sort of manner and you'll see some definate improvement.
=ASM hacking is the solution to all lifes problems=
No it's not. If your game is shit, it's not because you don't have the gun you want in it. It's because your game doesn't feel good to play. Your modding Cave Story, an almost perfect game, it has all the capabilities to produce a fun mod without hacking. Saying that your demo is unfun because you don't have a hack there isn't right, it's unfun because it's unfun. Stop using this as a crutch and expect more from yourself.
=Unfinished=
We all know why this happens but I'll say it anyways, sometimes you come in with an idea way to big for it's own good. This is probably your first dip into game design, and it should be treated as such. There should be more mini mods out there where people experiment and learn how to do things. You can tell which mods a person learned as they went with. Like that crappy mod Towers. The designer clearly made everything as he learned and the maps are each based off of some new TSC technique or hack someone made for him. It isn't cohesive, and trying to finish a game that's started off poorly is extremely hard. Also don't ask for help unless you show your capable of producing your half by yourself. Don't ask for tilesets until you've built maps with placeholder art, don't ask for super ASM hacks until you've experimented with what you can do without, and never just drop out of the face of the Earth if you can't finish and someone helped you. If someone did something for you they invested time in you, and if you can't finish they deserve an apology and some explanation.
=Not taking Critisism Seriously=
If you have someone test or play your game, the majority of the feedback you receive will be about bugs and typos. But what I happen to see alot of is the few comments made about gameplay, or difficulty are ignored or thrown to the side. Alot of the times a mod maker will say that, "it's because it's not done yet" or "It's supposed to be super hard" or at the worst, "YOU JUST DON'T UNDERSTAND!". There is a rule of game design that you have to know when receiving feedback, you are the WORST judge of your own content. You know every trick, secret, strategy and script in the game. If a player tells you they can't figure one out, it's tempting to just say it's because something's wrong with them and that you're doing just fine.
A good thing to consider though, if someone makes a specific suggestion on how to fix a problem, "you should get rid of the bats in this room" they aren't nessecarily right. Those bats may be the only challenge in that room. So what does this mean? It means that even though what they said isn't nessecarily right, there is still a problem. Take a look at those bats, why would someone want them gone? Let's say for example, you haven't given your player a weapon. The issue could be that the bats are frustrating because they are hurting someone who can't fight back. Or that there are too many in a space that you have to move in between. If you have given them a weapon maybe they deal too much damage for the players health, or maybe the bats have too much health. There are alot of possible problems, and these small issues really shouldn't be ignored, as if you keep designing rooms with these problems, they will add up really quick.
=Lack of Atmosphere=
Now only a few mods have done this one right, "WTF Story, anything made by Ralren" but atmosphere is something that makes your mod really nice, and even makes people pay less attention to any flaws your mod may have. Atmosphere is something that makes people lose themselves and get stuck in your world. It's what makes your world believable to a player. Great video games out there that are ripe with atmosphere are Metroid Prime and Batman Arkam City. Alot of mods don't have atmosphere, then tend to just seem like... well mods really. Your're constantly reminded that you're playing a game by bad tile placement, invisible walls, and in general things that only happen in games. Other than avoiding these obvious things, what you need to capture atmosphere is lots of detail.
It's fairly easy to fall into this trap if you don't care for your mod as much, but if you do, add detail. Put in little story pieces, "dead bodies, broken things, signs of past events in general" and don't tell the player about them. Let the player see these elements and infer their meaning on their own. You don't have to tell the player much in a game if your design makes sense, because their imagination is a much more powerful tool than you think. This can be applied to alot of things actually, but I'll get to that later.
Other important details to have are interactive ones. Let the player interact with the environment. Whether it's letting them press down to read about things or letting them destroy weak structures, giving them an environment they can interact with makes them feel like they're a part of that world, which is amazing. This generally requires work, but as you can tell, if you want to make something good, you kinda have to do work.
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This post will be continuously updated. The modding community here is bad. No other way to put it. BAD. So I want to try and move it in the other direction.
Hey, if you are working on a mod or have released a mod, I won't use it for reference without your permission. If you would like to give me permission to use your mod in reference in an above post, please let me know, and I'll be sure to mention the context it's used in to you if it is negative. It would be a good opportunity for you to apply changes to your mod if you so desire. Critique matters, and I'll be gentle. Use ranges from pictures to in depth analysis, regardless, I'll warn you first.