-Fascinating blocky 3D sandbox graphical style.
-Brief but good music.
-Day/night cycle leads to a perfect balance between adventure and creativity.
-No-so-obvious combinations and arrangements of blocks and items yield amazing results. People have built functioning digital clocks, elaborate vault doors, lava traps, pork processing plants, all sorts of creative stuff.
-The perfect type of game to play with friends, personalities tend to become obvious within Minecraft. More aggressive types will spend their time raiding and plundering whereas the more meek might stay within their own fortress walls and bake bread. Collaborating on building cool things is also a lot of fun.
-Notch's updates to the game will continue to improve it over time. The game is already an amazing achievement for one indie developer.
-No in-game direction or tutorial.
-Some sound effects could use tweaking or more variation.
-Several graphical bugs and bugs that will cause the game to crash.
-Extremely limited AI. Enemies and villagers tend to do one of two things: look at you, and move towards you. There is also a fairly limited number of enemies that you have to worry about and only one boss.
-Multiplayer is rather difficult to setup.
-I got the feeling that there are several elements still missing from the game. I found myself wishing there were more block types, more animals to domesticate, more food to grow, and higher level items to obtain. But I do hope that Notch will continue to respond to player requests and evolve the game into something extraordinary.