Got this for about 10 bucks more off mothership (free shipping). The only issue I don’t like is the buttons do not have clear markings and they don’t light up. Battery is like just over an hour. Needs just about total darkness to be effective unless really close range to the wall/screen.
Sound? Sounds like a transistor radio.
HDMI: Purchased a couple of mini-hdmi to full size hdmi cables. I had movies playing from my samsung tab 2 and laptop. If you get one of those battery supply backups, you will have houses of playback time.
Used mine this weekend at a campout. The teens (and adults) found it to be pretty cool. I used some Goal Zero speakers for output.
About the size of 2 deck of cards.
When you buy this (and you should), do yourself a favor and buy an external battery, a really big thumb drive, and a mobile speaker. Load video on the thumb drive, then you are good to go anywhere. I also take a tripod with me when on the road. You will need a dark room, but this thing will do a 60-80 inch projection on a wall in a hotel room nicely. Picture is not clear enough for reading small print, but handles movies and TV shows well. If you have WIFI, a Fire TV stick makes this killer.