I recently played Kosmosaurs with my niece and nephew. For context they are aged 7 & 5 years old. The system is a really odd mix. In its favor its super simple and the mechanics reflect that. it's in fact too simple. Many basic mechanical supports and rules that should be in this system simply don't exist. To put it bluntly it's a mechanical train wreck. If it's so bad, you ask, why would I give it three stars? I gave it three stars because the implied setting and the GM tools for creating story on the fly were actually amazing. I would run this again, for the right group of kids, and continue to just quietly fix things without the kids realizing what I was up to. The story and setting support was amazing and is worthy of praise.

This is an excellent small adventure, from a story perspective. With that being said, it isn't adapted well to 5e. To be truthful, however, there is so much good content here that I would still pick it up. Their stat blocks will do in a pinch, though given a chance I wouldn't rely on them too heavily. This is very OSR and assumes you are ok with your players acquiring allies. I suggest you let them since the success of the adventure depends on cannon fodder, but I would equally not shy away from their deaths or the consequences of them in a role-play sense. Overall it's a solid little adventure and worth spending time on it to spruce it up.

This is, hands down, the best suppement that has currently been produced for 5e. It answers so many questions and solves so many issues that is the official material. To say that it is well written or well thought out is an understatement. To put it simply if you are DM'ing 5e you need this supplement. Considering how superior this is to anything else that has been produced I'm sincerely surprised that Wizards hasn't contacted the wqriter to turn this into an official print product. Save yourself a ton of problems and get this book.

I wasn't sure what I was getting here. What I got was a load of awesomeness. This has a ton of character sheets to cover most, though not all situations. I think the most likely issues that will crop up are during multiclassing and even that has a fair attempt made here. This is truly a stellsar collection and I will be using these heavily in the future.

Interesting take. The ideas are well thought out and fairly well implemented. The art is decent, but sparingly used. The magic system referred to in the material is more implied than spelled out. I will take a star off for that as the crafting system for magic in 5e is too basic to be of any real use. With a subtle hand this could easily merge with the system presented in the comprehensive equipment guide. Overall useful enough to just justify the price, for those who seriously intend to use it.