There's a demo, so if you're really curious try it out.
I purchased the game when it was on sale for under $4.00 and think it's one of the best deals I've got on PS Store to date.
It reminded me of House of the Dead Overkill for the PS3.
I've only played the first two chapters out of seven chapters andt based on what I've played, I like it and don't regret the purchase. Really can't understand the negative review Gamespot gave the game, maybe it plays terrible on the PC but on the PS4, it's fine.
You control the game with your controller by using the built in motion sensor. To get power ups and perform some actions you have to swipe the pressure plate on the controller. If you find your aiming reticle is off, you just press L1 and it move back to the center. A friend said he had problems with the reticle but I didn't.
The game looks nice, it doesn't look like a cheap piece of crap.
I found the story and the characters funny. What sold me was one of the first times I got a headshot, you get a little blurb that comes up with points saying "Warning Headshot" - that made me laugh.
The game has three difficulty modes and I think you get about 4 continues for each of the 7 levels. There's a story mode and once you finish a level, you unlock that level in an arcade mode.
There are 13 trophies. The game keeps track of your score and shows you how you rate against your friends and the world.
If you're curious, the game installs to 3.99GB and the save file is 10.49MB.
For what I paid, it's pretty damn fun. Even if I had paid full price for the game, I don't think I would have felt ripped off.