Even on very easy, I could not beat the first level.
Problems I ran into were a strangely short attack range (often having me inch closer pixel by pixel until I could hit), gameplay that overall felt laggy and slow, and the enemy having a far larger range of attack than me.
I suppose the biggest problem, though, was that I had some trouble realizing that I was supposed to kill the creatures, as the game seems at its most fun when trying to run past them. I was really confused when I got to the end of the level and nothing happened :P
The time slow mechanic is nice, but it charges too slow for how long the effect lasts - and the effect (at least in this level) does not even seem terribly useful.
On the good side of things, it is really pretty and has some creative ideas there. The option to remap buttons is also a major plus, which got you an additional point on engagement (because I had no idea where else to put it).