I will preface this by saying that this is a couch co-op game and has nothing to offer if you don't have a friend sitting beside you to play with.
Screencheat is designed solely around one elevator pitch idea that you cannot see any other players on your screen (they're invisible), so you have to "screencheat" aka look at other players' screens to figure out where they are and shoot, stab, or otherwise kill them. It looks and feels like a tiny little indie game that should cost a couple dollars and gives you some great laughs with some friends. In our current game market, there is a desperate need for good couch co-op games, and this fulfills its promises. It is equal parts fun, challenging, and silly, and well worth a couple bucks; the problem is that it costs more than just a couple bucks.
Overall, if you can get it in a bundle for just a few bucks, or just buy it on sale, then yes, it is worth the buy. It is not worth the buy at full price
On sale: Worth the buy
Normal Price: Not worth the buy