New procedural terrain demo; More Instant Games updates; Lots of bug fixes.
Thanks, I'm glad you liked it! We don't impose any limitation on the size of the dictionary, so it's upper limit is the JS heap size. You could switch to using localstorage instead, which is likely slower but would increase the max size to available disk space and effectively "save" the world for players. There are also ways to store the data that is more space efficient ( binary instead of JSON, run length encoding, Huffman coding, etc. ).
The grass error is a bit of a pain, but it's quite minor. I haven't investigated fully, but if my best guess is correct then most fixes will have semi significant trade offs. Still, fixing it is a good exercise for the user!