Ah, Black Paradox. Another horror manga that relies solely on its disgusting premise and makes no effort to try and carry a plot or decent characters. Boy, do these get boring after a bit.
During a goup suicide attempt, something goes wrong and one one of the group somehow ends up with a portal to another world in his stomach. Blah, blah, blah, gross stuff, blah, blah, blah, everyone goes a little insane, you know the drill.
This is so similar to the many other series of the same genre it's painful, and comparitively it doesn't even have that gross of a plot, so it doesn't even match up with them.
Sure, if you like this kind of series, go for it. Otherwise, a) there are plenty better ones out there b) just avoid this style of series altogether if you don't like gore.
Review for November 2016 DMMC
Average but as usual fairly interesting while reading it. The first chapter is more promising than those that follow. Honestly i can't say that much about this manga because while not bad it's ultimately forgettable.