When asked whether or not you should consider purchasing this game, you should take this single factor into account. It is an older indie title with no single player mode. It is not nearly as popular as many other titles like this, and thus it will be very difficult to get into games, unless you are either very lucky, or the more likely scenario, you bought a few extra copies so you could play with your friends.
I do not dispute that some people must be able to get groups together to actually experiance what this game has to offer, however given how tiny the community for this game appears to be, the likelyhood of you being online when a match is goign to be played is very low. Being a review, I can only judge the game on what I see, and since after a week of owning it have not been able to get into a single match, have no opinion on it other then, it really should have a single player mode.
In its current state, I wouldnt to recommend a purchase unless you know a few other people who already own it, or will purchase extra copies for them. Thats a shame, because the game does look fun, I will just never experiance it.