Are you referring to the floating snakes, or the yapping maw ones that grab you? I'll give impressions on both.
The floating snakes seemed to work quite well, floating around until you get close, then flying towards you. It makes them seem very territorial which is cool. They are pretty easy to kill at a distance though. If you shot them when they are in their neutral cycle, it might be better if they were alerted and came after you.
The Yapping maw ones worked well, but were not very threatening. I found that I could run past them quite easily, either because they were slow to grab me, or didn't react fast enough to my presence. However I did fall into a pit beside one, and it grabbed me through the wall and I got stuck. One time I got stuck in the wall, and another time above it.
I also noticed the bombs float when placed over a cliff. It would be cool to be able to drop bombs over an edge to defeat enemies.
Sequence breaking could be cool, in the way of secret passages and such. In Super Metroid most sequence breaking has to do with abusing your abilities, but since most of them are absent in your game so far, a less linear approach to level design might work equally as well.