Edited: 9-17-2020 UPGRADES!!!! I added some pics with an upgraded scope, new string, and aluminum bolts. I've have had ZERO misfires with the new bolts. Group at 10 meters with minimal adjustments.
First, this is a weapon, not a toy. If you're not taking the time to set it up and make sure all the parts are secure and undamaged, you're setting yourself up for failure, let alone pain or worse! This is a fun little crossbow if setup and used correctly, BUT! I received the crossbow and within the first ten shots the string started unraveling. I returned the entire thing and and received a second crossbow that lasted about 30 shots before again fraying and damaging the string. I was very frustrated and disappointed at this point and decided to sleep on returning it a second time in less than 24 hours. Maybe all the bad reviews were right after all... Day two I did some research and here's what I found:
1. BUY WAX AND WAX THE STRING AND RAILS BEFORE SHOOTING EVEN ONCE! The string is plenty durable, but is very dry and friction is you're enemy here. Applying some $4 bowstring wax (there are household alternatives) to the center where the string contacts the bolt and rails will protect the string from heat and damage. You can also apply a thin layer of wax directly to the top guide rails to help reduce heat.
2. Tighten screws, but not too tight as some parts of the sight screw directly into the plastic and can be damaged. Assembly is not well documented, but straight forward with the exception of the string (more below).
3. The sight adjustments are simple, but parts are VERY flimsy. If you're looking for anything more than fun target practice, you may want to upgrade. There's a dovetail rail for adding scopes, sights, or conversions to more popular types.
4. The safety switch (or sudden movements for that matter) can bump the bolt too far forward when engaging/disengaging causing the string to ride over the bolt and not shoot correctly (or at all). I know most people claiming they can't shoot more than 5 feet are having this problem. Be sure the bolt is in the correct position (may need to slide the bolt slightly forward or back) if you are not having success shooting.
5. Stringing ANY crossbow can be very awkward and frustrating. It may be worth searching for "how to string a crossbow", but it only took me a few seconds and nothing was damaged in the process. Keep in mind if you bend or break any part, it may no longer safe to shoot. Again I have to stress that this is not a toy and does require some technique and/or strength.
Hope this helps!