Brining gaming and crowd-sourcing into memory training is interesting, since this kind of learning has traditionally been a very isolated practice.
In our experience, we've found that creating your own mnemonic is usually the best way to really deeply encode a new memory.
But a great mem from someone else works almost as well. And it's a lot easier to breeze along, giggling at other people's imagery, occasionally coming up with something new of your own.
We've improved the underlying algorithms a lot since then. Do let us know if you still find the garden confusing.
Sentence building is definitely on our radar, but it's a rich and thorny domain, and we want to take our time coming up with something good.
P.S. Android is going to take a little longer.
Are these algorithms any different than the ones used by Anki et al? I'd be surprised if they were. The novel thing for the isolated case (gamification is interesting but I'm not sure how general that is for helping) seems to be thickly layering on the mnemonic tricks instead of relying on pure flash-card memorization of information, is this correct?
http://www.wired.com/medtech/health/magazine/16-05/ff_woznia...
However, neither Anki nor SuperMemo enrich and speed up your learning with mems (crowd-sourced mnemonics), which provide a huge and well-documented boost to your learning rate and retention.
Perhaps most of all though, we've worked really hard to make Memrise a really happy learning experience. It's harder to put numbers on that, but hopefully you can feel it when you try it!