The NES version of Kid Niki has secret rooms all over the place. They're pretty well hidden, though, and I probably wouldn't have found them without the help of an old tips and tricks video I got a long time ago.

Like this one on the first stage.

Make your way to 1-9 and position yourself like so:

Then duck for a bit. Maybe hit the B button a few times to spin your sword around.

After a few seconds (and usually right after pressing B a couple of times) you'll be transported to a secret room!

Unfortunately, there's not a lot in this one

But there are a few others later on that have lots of bonuses, which we'll talk about another day.