Definitely to the end, especially if you’re commenting on its story or are going to be recommending any of the hacks. Looking at only half a hack is no better than looking at an unfinished hack IMO, it’s only a portion of a work of art, one of the most drastic examples of looking at a game only halfway through is if you played DDLC up until the first [OH NO] happens and the game first resets you’re just going to think it’s an average dating system that ends abruptly and nothing else.
as long as it’s something you enjoy it’s definitely a good idea, you can look at units that are under or over rated and I personally believe that units from hacks are generally more nuanced than vanilla gba units, you only get one character as middling as isadora in fe7 but in a lot of hacks the devs play around with unique concepts that can make units far more interesting.
In my opinion a more comprehensive review that definitely reflects on the person’s thoughts on the whole product that took months to create is more valuable than a less comprehensive review that only covers a portion of the game and may not even accurately depict the person’s thoughts on the whole product that took a month to create.
Don’t worry about taking your time with things like reviews, it just means you’ll be more thorough and be more valuable to the creators as a person who has played their hack and cares enough to provide feedback and their thoughts on it.
I see, I see. It’s nice to hear back from people like you!
I should also mention that I don’t usually play hacks that are completed from like the day they’re released- usually I give them a week or two to account for the (sadly inevitable) bugs that pop up and the time it takes for a bugfix to come out.