I really rather like this game -- it's cute, fun, and rather innovative.
As has been mentioned, it does seem to feel rather repetitive at times, but is overall well done, I think. Perhaps a wider vocabulary would be nice, or a more rapid appearance of words.
I did find a bug, however, which I would consider game breaking. It saves progress automatically, sure, in every regard but one -- money. If you buy an upgrade, it logs that immediately. However, if you then reload the page without closing the shop window, you will have your money back, and the upgrade.
For example, I presently have 200 gold. I bought Armoured 1 (because I'm slack that way), for 100 gold, leaving me with 100 gold. I then refreshed, without shutting down the shop window. After clicking Continue and checking the shop... I have Armoured 1, and 200 gold again.
I bought Armoured 2 for 200 gold, leaving me with 0 gold. After refreshing, I again have 200 gold, and Armoured 2 still.
So... Yes. Infinite money rather ruins the shop, but otherwise, this is a really enjoyable game. I rather love the background, too; it feels... Appropriately textured. ^.=.^