A video if you have an interesting voice and good animation skills, written articles if not. Both need to be well-written, but try to make a couple short videos (5 minutes) and read the feedback; if people are saying that you are monotone, that the videos aren't funny/interesting, that the art sucks.... Maybe that path isn't for you. Written articles can be just as good or better than videos, provided they're well done.
As for style, humour is probably the best way to go, because that seems to be what most people are looking for. Avoid making the obvious jokes (Call of Doody) and you should be fine.
That said, MAKE SURE YOU WANT TO DO REVIEWS! If you want to make jokes about games like Unskippable, or talk about bigger topics like Big Picture, do that; don't say you are giving a review, and then give us a stand-up sketch or a dissertation. Both of those can still be good, but avoid false advertising.