First impression? AWESOME.
Haven't had any problems with the puzzles or anything so far. The only criticism (if you could call it that) would be that there's too much fog. It seems to come every five minutes and over the last ten hours straight that I've been playing, it's become quite annoying. Heh.

This game seems to move faster than the earlier ones, which is gratifying.

It's also a bit annoying to have to keep a builder permanently at the base of the waterfall to stop the stream clogging up, but once you've got a few "spare" peeps it's not too bad. Till then it's just a bit of a juggling act.

Overall, imo this is the best one so far! In every aspect! Good work everyone, and thankyou so much for bringing yet another top quality game to us obsessive types.