After about a billion attempts at that last level, I finally got the hang of it and finished the game, lol.
I think that having spikes that only sometimes kill (or that at least gave the appearance of this) was not really the best idea, and it's the first time I have seen invisible pits, haha. But I am not an artist and I perfectly understand the difficulties in drawing clear distinctions between objects in only 2 colors and a few pixels. :)