I didn't notice too many spelling errors, but then I sort of glossed over the dialogue in my rush to finish the demo.
I am debating whether or not it's worth buying. With Avernum 1, and 2, it felt like there was alot I was missing out on in the demo that I could get in the full game, whereas here, I'm just not that excited to see the rest of geneforge. I think that part of it is I wish the world design where a bit more creative. Here, it's basically just forests, towns, swamps, all of them a bit generic. With the avernum series, it stood out because of the caves.
I really liked the creator level, with that wonderful use of red lighting. Spooky.