Adventure Crafter is a useful genre-neutral and game system-neutral tool if you're looking for inspiration when creating key moments in an adventure. It's modular, meaning you can employ or skip various elements as you see fit, and the tool still works. I recommend it.
You can use Adventure Crafter for solo play, or as a GM you can use it for inspiration on the fly or for planning in advance. You could use it for a one-shot session or an on-going campaign. You could use it for a single scene, or for a series of scenes. You could use it for GMless play to help you create scenes, but it doesn't include an answer oracle that handles questions like "Are there monsters in the room? Is the door locked? Is it raining today?"
The core element it deals with is the Turning Point: "Turning Points are the pivotal Scenes in your Adventure that propel the story along. They are the plot twists within your Adventure." Each Turning Point consists of "plot points" you select or roll up from one of five styles: action, tension, mystery, social, or personal. I had to get used to their use of the term plot point. Outside of this product, a turning point and a plot point are pretty much the same thing to me. What Adventure Crafter calls plot points would have made more sense to me sooner if they had been called tropes instead.
There are 40+ "plot points" that cover various things like what happens in a scene (someone runs away, mass battle, corruption, etc.), who's involved (an old nemesis, someone who needs help, etc.), or the circumstances of a scene (small town, night time, etc.). It's then up to you to fit these pieces together. There's also nothing stopping you from discarding elements that make no sense. There are various ways to use each plot point. For example, if you roll up a Mass Battle, the battle could be the trigger for the scene, or it could be the action within the scene, or the scene could portray a battle's aftermath.
Each of the five scene types (which Adventure Crafter calls "themes") uses its own mix of the various plot points. This is a strong point of the tool, because you might want one scene to emphasize action while another emphasizes social elements, for example. You whip up a short theme table that lets you prioritize the themes. You roll up (or choose) one of the themes using that table, and then you roll up a plot point for that theme. Do that five times, and you've got the ingredients of a Turning Point. You can get up to three "None" results, meaning you'll end up with 2-5 plot points per Turning Point.
Many of the plot points invoke new or existing characters. You maintain a character list that also serves as a table to roll against. When a plot point mentions a character (such as, "A Character acts in a very risky way"), it's up to you to determine who that is. You could make the decision without rolling dice, but the character list is there if you want some randomness. At first, the entries are a mix of "New character" or "Choose most logical character." You overwrite entries with characters who are likely to be involved - the PCs and key NPCs. As you roll up plot points, you'll also start adding characters to the list. This is how Adventure Crafter adds continuity from one Turning Point to the next, by involving characters that appeared earlier. Adventure Crafter provides general-purpose Descriptor and Identity tables to help you make up new characters, but you could easily use your own methods for creating new characters.
Similarly, you can keep a list of plotlines. For a one-shot or a tightly focused session, you might not want multiple plotlines, but if you're willing to let plotlines accumulate, you can keep a list and roll against it every time you create a Turning Point. Like the character list, the plotline list is a mix of "New plotline" and "Choose the most logical plotline," and you add to it as new plotlines arise.
A possible shortcoming (depending on your expectations) is that Adventure Crafter doesn't produce anything like a goal, logline, or elevator pitch for the adventure, or even for an individual scene. Most of the plot points don't give anyone a goal. It's up to you to come up with these things, whether you decide them before you roll up plot points to guide your interpretation, or whether you use the plot points as inspiration to see what emerges.
Another possible shortcoming (again depending on your expectations) is the lack of plot structure. It does indeed discuss making an adventure outline, and it achieves that up to a point by having you string together a series of Turning Points. You could, for example, make an action opening by emphasizing that theme for the inciting incident. You could throw a mystery into the middle. You could have a big action scene saved up for the end. That's fine as far as it goes, but the tool makes no distinctions between the different stages of a story arc. If you want your Turning Points to follow the Magnificent Seven Plot Points, the Blake Snyder Beat Sheet, the Lester Dent Pulp Master Fiction Plot, or the Spirit of the Century Pulp Plot Framework, it's up to you to impose that on the Turning Points you create.
Adventure Crafter is written clearly (aside from the terminology quibbles I mentioned above). There are good explanations for each plot point. There are a good number of useful examples. The PDF includes a few pages ready for you to print out so you can write on them and have them at your fingertips during play.
Adventure Crafter is a nicely done tool. I recommend it.
[5 of 5 Stars!]