We need ideas for a two-player/co-op mode of The Legend of Zelda (NES)

We're a Let's Play channel and the two of us are playing LoZ together and trying to create a new, co-op, 2-player kind of experience. We're a few episodes in and we've used the following:

One player is blindfolded while the other gives instructions

We each hold half of the controller

One of us plays while the other one of us slaps the player when Link takes damage (that's a FUN one!)

We trade off control every time Link enters a new screen

We are having a fun time so far (we're a few episodes in), but we need some more ideas to keep the game challenging and entertaining (but not TOO tough in the later levels). Thoughts?