Pretty nice game! At first glance, I thought we were moving through random parts of human body, only later I noticed, that these are actually organs of the same human XD
More enemy variety, organs-exlusive enemies would also be great and as majikarpette mentioned, a visual of a legit floor we're moving on.
Also, you can press space at the beginning of the level, sometimes enemies won't be able to catch to ya and you can skip organs entirely this way.