Jets'n'Guns is a Shoot Em Up, also called a 2D sidescrolling space shooter. I have spent at least 200 hours playing this game by myself/ when I was younger and I instantly bought this game on steam.
There's an insane number of weapons to buy, you can level them up, you can purchase upgrades for your ship, pick a combination of weapons you like depending on your playstyle. There's also a good selection of bombs and missiles.
The music is amazing ( 30+ soundtracks from Machinae Supremacy, an amazing Sid Metal band, ) the replayability is good, they added achievements, trading cards, some tweaks and it works on 1920x1080 resolution. I recommend buying this game in a heartbeat if you liked any kind of space shooters because it's always been my favorite one and you will definately like it.
After playing for an hour or so, I can tell it's just as good as I remember it, but, I also used to play on easy and I just tried hard, way too hard for me, normal offers me a fair challenge and the game is very enjoyable. :)