Nice change of peace from usuall top-down shooters.
It gets quite easy once you get used to mechanics.
Later missions are quite challenging - but that's only because they put more and more enemies in bigger and bigger rooms.
Some workshop levels are also nice.

I enjoyed it - but that might be caused by limited amount of time. Doing 2 or 4 missions a day is ok - but ifI would play as Iused to-for example 4 hours in one go - I would be bored and probably abandon it in halfway through xD