No, it's not minecraft.
This game is very unique and fun, despite people constantly referring to it as a minecraft rip-off. With the "you dig, you craft it's minecraft" generalization. Although it has similarities to the elements of minecraft basics, in 2D. The gist of the game do not tie together to minecraft at all, however you may play it as a 2D minecraft if you wish.
You start out by having a set of copper tools ready at hand, destroying a tree that collapses, collecting resources to craft a workbench. Then stone blocks can be made into a furnace from crafting it near your wooden workbench that you have made. Again, very similar to minecraft. Except it removes the feature of shaping the items you want to craft. The next stage is digging/creating a temporary shelter. Because without a shelter at night, you will most certainly die at a new start of your character. Soon you encounter rarer items and ore in natural occurring caves. Caves really do feel like caves in this game, with overhanging vines that blocks light and grows over time, you can easily dispatch these with a click of your mouse, monsters that will spawn offscreen and harass your exploration from time to time.
What is different you ask, what is new? This game isn't afraid to introduce you to combat, you can stack potions, and take them within interval delays in combat. Your character have 5 accessory slots, each can be filled with a status affecting item. Such as a horseshoe that makes you immune to fall damage, or boots that makes you run faster, or a cloud in a bottle that makes you double jump, some of the items stack in effect! You gain an increase of health by exploring caves to find heart crystals, and gain mana increase by collecting falling stars that drop randomly at night. After your discovery of the golden armor and weapon tool sets, you are ready to move onto bigger things! The visually different biomes to explore! First you will encounter will probably be the corrupted zone, an area of worm beasts, and flying monsters. Each cave is no longer horizontal, but vertical with a fall shaft that might lead you to the boss worm's egg, in game they call it a shadow orb. After destroying about 3 or so, a huge worm boss rise from the ground up to eat you, each of the segments of the worm has separate health points and do separate damage, when you split him up in two, the section starts off as another segmented worm. This guy makes you jump and run to dodge his attacks from ground up, and down. Swinging your sword in session of clicks while scrolling back to drink that potion to keep you alive a little longer. Earning victory -- will get you closer to collecting a new armor set.
It is battles like that which makes this game different. Biomes and areas are the main gist of this game, the exploration of it all. You will encounter many different places, such as underground jungles with flying hornet and chain chomps disguised as man eaters. And a dungeon with a skull boss -- only after defeating him you are able to proceed in to loot, but the dungeon is still invested in many of his underlings!
Most of Terraria's game bosses are able to be summoned again, to grind for your gears, but the different chest containing areas will remain empty once you have finished looting. So that might make you wonder, how could I collect them all? This game keeps your inventory for that specific character, in multiplayer and single! So players often strip worlds; generate a world, run around collecting loot, fighting bosses, delete it, repeat. Which makes it like a realm of different worlds, seems much like the diablo 2 multiplayer character-inventory system. The single player world is easily host-able on multiplayer, with in game selection of the worlds you want to host, then BAM, everything you made will be kept that way online. No need to import files or any of that sort.
There are many things I haven't explain, because in the end of the game, at whenever you feel it is completed for you, those things won't be as necessary. But I'll give you a general rundown, NPCs comes to your home when you have built a correct shelter for them, in size and in setting of items. You are able to customize your home in any way you like, such as the backgrounds, adding shelves for books, candles -- want something fancy? chandeliers all up in this. Randomly generated events, meteorites! Turns those blocks of random dirt and rocks into meteorite blocks, you best know that you need them for special gear! Goblin invasions -- damn thieves stole my lawn. Eye of cthulhu -- wait til you see it's transformation!
With many content like that is what Minecraft lacks and Terraria excels at. If Minecraft was 2D, Terraria will certainly best it in all contents. But considering both games are sort of in a beta stage, with their developers still adding in content, I hope comments will be kept at bay for comparisons. Until next time, shut up and dig gaiden.