Blockland is crackable, just nobody has done it yet that we know of. Call it unhackable and someone will do it just to prove you wrong.
The game authenticates with a server online which makes it more difficult to generate a key because not only do people have to guess keys that look close enough to the real thing that the game expects them but they also have to guess actual valid keys that verify with the server if they want to play online. If you guess a key someone is already using you won't be able to use it at the same time as it, and the key will eventually get deactivated if it looks like it's being shared.
Using a cracked copy will keep you from playing online with legitimate servers. You will be restricted to singleplayer and whatever hacked servers people put together. You wouldn't get autoupdates. You would almost always be a version (possibly more than one) behind everyone with a copy they purchased because each new version would need to be cracked again. Playing online between cracked servers itself would probably be difficult because one server could be running v13 and another v14, due to no autoupdates, scattered releases, and slow updates, and you wouldn't be able to connect to any except the ones that were your version. RTB won't work for you either, you would have to download mods off the web.
It's probably more worth the time just to make a new game. In fact, that's what people tried to do with Blockland Source and TBG.
All games should be made this way.
Yeah, like Asassin's Creed II? That totally didn't get cracked. Requiring permanent online authentication for a game is a horrible thing to do to your customers. Blockland did it the right way, you only need the Internet connection to play online (which you would need to do anyway) and offline mode lets you play singleplayer. It allows some minor abuse by people but nothing major. Other games do it this way too, in some you don't even have to enter the CD key until you start multiplayer.
Its amazing how all of the indie people make simple systems that stop there games from being pirated (Usually) compared to large company's like EA, obviously there security programmers are useless or don't honestly care. Always some marketing douche that comes up with idea's like SecureROM.
SecuROM, Starforce, etc, are horrible and you should just be able to install your games and play them without the disk (unless it's some kind of space saving install that needs to load data off the disk which I'm fine with but it's also very rare today). But I tend to think it's more security through obscurity. There's no TV campaign, it's not in stores, the publisher isn't moving millions of units to the market, so demand is comparatively low and software cracking groups just don't care when they've got Starcraft II and the new 3ds Max/Photoshop/etc that comes out every year to crack.
