I bought most of the PDFs for Star Trek Adventures a long time ago, but didn't get to run it. I love the setting, but I didn't love the rules (at the time). But after some time running some other settings where there's a lot more crunch and funny dice with my regular group, I thought this might be worth a try. Having the PDFs makes sharing easier than having only physical books.

But the layout of the core rulebook is a little convoluted. Sometimes something is used before it is explained, and there's a lot of fluff mixed in, making it harder to find the specific section you need later on. Sort of by accident I bought the Tricorder Collector's box on Amazon, and it came with the digest rules. At first, I thought it was a bit of a waste since I had the Core rulebook, and figured I'd just use the book at the table to pass around. I really wanted the box itself for a project. Well, after looking it over, I bought the PDF of those rules here as I much prefer the layout. It works better as a RPG rules book than the original core rules by quite a bit.

Technically it is redundant, but it's that good. I'm only writing this review because there weren't any reviews mentioning this on this product (there are others stating this on the Core Rulebook, but you won't see those if you just look here).

The system is pretty easy to pick up. There are vague similarities to other system like Star Wars RPG, but it is much easier to play with normal dice than that game, which requires either specialty dice or the app on smartphones to be played functionally). You generally have 2 to 5 d20s you'll roll. You want low rolls. The specific number you need depends on your character's stat + department. If you have a focus that applies (each character has a few of these, like Xenobiology or Philosophy or Subspace Theory) then really low roles (equal to or below the department you are using in the roll) count as 2 successes. Extra successes beyond what you need build momentum, which is a group resource that anyone can use to buy extra dice on a critical roll.

If you don't have enough momentum, you can instead give the GM Threat to use on a 1-for-1 basis. This is very similar to the Light Side Dark side destiny system in the Star Wars RPG game, but isn't a zero sum system. I much prefer this method as momentum and threat can build and be spent separately so neither side and "freeze" the other out by refusing (or forgetting) to spend it. Some weapons will build threat automatically, which explains why Trek ships don't pull out photon torpedoes at every opportunity (much like knives and guns don't get pulled in every fight in the really world, either).

Finally, some rolls will also use 6 sided dice (for example, combat, but also extended tests) to determine the specific effects of a successful roll. They have specialty dice you can use (which also come in the tricorder box I mentioned) but they really aren't needed. The six possible effects are: 1: 1 stress 2: 2 stress 3: Blank 4: Blank 5: Effect 6: Effect

The roll that say, "Effect" cause 1 stress, and trigger one use of the special effects in play. Typically, that depends on the weapon being used. That might be extra stress inflicted, or ignoring some of the resistance of the target, but it could also be a loss of power, additional automatic hits caused, or damage over time). Finally, the total amount of stress you rolled is totaled and reduced by the opponent's resistance. If there's anything left over, they lose that much stress and if you do 5 or more, there's an additional effect. In personal combat, that's an injury (they are seriously wounded and out of the fight). In Extended Tasks that's a Breakthrough (you need a number of these to succeed, so a really good roll might let you succeed earlier than expected), and in Starship combat these are hull breaches and can take out a system completely. Finally, high results on the d20 can result in Complications. The simplest of these are additional Threat, but other results are possible, such as destroying a control, or hitting an ally. Normally these only result on a natural 20, but that can be lowered due to existing complications or certain character traits, perhaps in exchange for additional (free) dice.

This same system is used in extended actions, so once you understand how it works you know how all the systems work. It gives you the opportunity to have unexpected results. You knock out the guard, but you can hear another pair coming around the corner, etc.