blockland is like runescape, it's "free."
you can play it for free, but the free part is stuffty, so you buy the extra features.
True in essence, but I'd say runescape offers much more for it's free version compared to Blockland.
Blockland offers you a taster of the full game.
Here, try this limited number of blocks, no multiplayer and little use for any add-ons.
Whereas Runescape still offers you a large amount to do, large quantity of items, and multiplayer too.
The best difference is simply Blockland having a 1-time payment for the rest of the game, compared to Runescapes continuous payment for "extras".