This is a relatively decent shoot-em-up game. However, I do have some problems with it. One main problem would be the sensitivity of the box pick-up/put down mechanism. It was quite flimsy at times, and if you were just a little bit imprecise with your timing, you would end up a block before or after the spot you intended to drop the block. This might add to the challenge, but it was not a fun sort of challenge, it was an annoying sort of challenge. This was especially annoying in the last stage where precise timing was essential to finish the level.
I also noticed one other bug. In levels 17 and 18, there would sometimes be an infinite death respawn. Because of this, people may have to restart the page just to play through the entire thing again just because of the death respawn at a particular stage. Now, this game has no save points (I have no problem with that aspect actually) and so if a player is met with the infinite death respawn bug at the last stage, they'd have to start from the beginning of the game if they intend to finish it.
Now the positives. There really isn't much to be honest. It works fine for the most part. The game puzzles were not mentally stimulating enough however, and the zombie concept is kind of overrepresented in the video game world already. Overall, this is a decent game to play, but it is not above average. It is fair for a game that was made in 72 hours.