Creative version: Sandbox mode. You have a palette of every block (except water, lava, and adminium) and you can place/delete them immediately. Levels or maps or w/e you want to call them are limited in scope.

Survival test: Early early beta of current Minecraft. Health, limited maps, no palette of blocks, and monsters.

Indev (still available but going to be removed): Early beta of current Minecraft. All the stuff in survival but with crafting, not as many recipes as current Minecraft.

Infdev (still available but going to be removed): Least early beta of current Minecraft. All the stuff of indev, but infinite maps (theoretical, you don't have enough storage space to get to have the physical maximum), more crafting recipes.

Alpha/Game: Most current Minecraft. All the stuff of infdev, but with more recipes and other changes.

And in the paid version, you can create custom skins for you character.

Want some advice? Buy it. Naow. It's one of the best games I've ever purchased. And you won't know the marvel that infinite maps are until you buy it.

Someone who bought the game could just be nice and gift it to him.
http://www.minecraft.net/gift.jsp

( I would, but my copy is gifted. >_> )

That's a very generous feature.

Well I'll do it then. Allstone, what's your username?

EDIT: Also, awesome caves are awesome:

Oh god... And that's randomly generated, right?

Fresh off the seed, absolutely.

My username is Allstone.
Thank you so very much.

Dammit man. You're gonna hate me for this, but I can't gift you the game. Notch has stepped back on free gifting, so I'd still have to pay the ten euros. I'm a bit short on cash (specially european cash), so, well, sorry. I hope you understand.

The free gifting was just a Christmas special.
If you'd bought it before then, you got a free copy to give to a friend.

Dang. Oh well, anyone here's got one of those?

I gave mine to DragonXP. Sorry.

That's okay. Thanks for the offer anyway.

Sorry about the misinformation! I thought it still worked like it did at christmas. X_X

Of course, in my post I never said it was free to gift, I just said someone could be nice and get it for him...
Anyway, Allstone, I really do recommend minecraft.

Yeah, thanks for it still!

You know, the worst part of mobs?
If you fall accidentally in dark, dark hole, there is always a huge mob of spiders/ zombies/ creepers/ etc... I've only ever survived that once.
P.s always keep a large stash of ladders in your inventory :/