Great Game, but can be better.
Guns are one of the main parts of the game. You immediately start out with a pistol, and as soon as you pull it out and shoot something, you think this game is amazing! Shooting down Zombies and Skeletons is cool indeed, but the main thing to kill are the dragons. They fly around, trying to kill you, so they are a challenge.
Another great factor about the game is the infinite terrain. You can go on forever and the game will never end, although at around distance five thousand, the game goes backwards. As you go through a plains biome, to a forest, to a desert, and so on, then you go backwards as stated. (Desert, forest, plains)
Now let's move on to the difficulty. Sure, challenge is great, but flat out annoyance is wrong. Every second on normal, zombies swarm you in the day, and even the weakest of zombies can take 4 hearts out. If you are not strongly prepared, you will get eliminated fast. Zombies can also glitch out and hit you twice, even three times, taking out almost all of your health! You must move and act fast to get away.
Aliens, which were added in the 1.5.0 update, are very, and I mean very powerful. You need all of your best firepower to take even ONE out. They can take eight hearts out on normal, so they should really weaken them down.
This game is great, even with it's intense difficulty, and how items you drop when you die despawn within 25 seconds. It deserves an 8.5. Good graphics, good game play, but very hard difficulty.