You get what you pay for, so I didn't expect much from this. However, my 8-year old wanted to buy this with his own birthday money and has been deeply disappointed.
The set consists of a small assault rifle, pistol, 2 clips of darts, and some 'binoculars'. The binoculars have pink tinted lens, don't magnify, and don't really do anything at all - their principal contribution to 'spying' is simply to obscure reality, and they were quickly discarded as worthless. The guns fire small darts with sucker cups, but the range is very feeble - scarcely 3 meters - and very inaccurate. Even when working properly, they are profoundly underwhelming. The spring mechanism on the rifle broke after 1 day of light use, and the pistol broke about a week later. The guns have welded / glued seams so can't be dismantled for repair, so these are now in a bag waiting to be sent back (hopefully for a refund - don't want replacements).
As passive toy guns, ie not firing anything, they are ok if dull - don't even make a noise now that they are broken. As working toys they are little short of rubbish, and not recommended at all.
If you want a toy gun that fires stuff, look at the nerf gun ranges - many of which are cheaper. They are very accurate, robust and huge fun. This set looks promising but really isn't worth having at all. Avoid.