Ergonomics and predictability of your next action outcome is really important in hard-metroids and brawler fighters alike i think, but controls (esp when it comes for telekinesis and wall jumping) in FI are not that responsive and/or predictable as a metroid fan would like.
Combined with the relative hardness it is a bit frustrating.
Oddities i encounter:
When a wall is near, a character can enter a sort of walljump mode without the wall.
Rocks sometimes get stuck on spikes or drift randomly by themselves.
The border between bouncing on an arrow and being killed by an arrow is a bit too vague. Sometimes you can just stand in front of arrow dispatcher and only get repeatedly tickled ^_^
I even thought that it is an intended mechanics for arrows but alas vertical ones are still deadly.
You can command a rock to go away while you're directly on it, it won't move (ecpectedly), however when you jump it can slingshot all of a sudden.
Also there is a (probably test level) in the area to the right of the space where you get once you escape the shakey doom. If you go to the right of the test level you will disappear forever.
Not that's it is bad, just leaving an exploratory note here ))