Congratulations on your first level. I got to the Forever's Plain, but there are way too many glitches before that. SGE's (the bottom of the waterfall in x1000y1002), wallswims (on x1001y998 if you fall down through the first invisible block, you end up wallswimming in the "invisible" block, which leaves you trapped since you can't climb), monsters wallswimming (go to x999y1005, wait a bit, and the right monster enters the wall at some point).
There are also various bad design decisions. For instance, most dangerous places in the level are easily avoided by using the hologram. At x1006y999 there's a somewhat difficult/uncomfortable jump; if you don't make it, the nearest savepoint is very far away. Not only that, but even if you make it, the logical thing is to jump into the air stream, and that kills you; so in any case the player is forced to go through several challenges at least twice. This part, and some others really seemed like you tried to make some really dangerous places to compensate for the ones that were not so dangerous; as a result you have inconsistent difficulty that puts players off. Visually, too, there's a lack of consistency: the screen I just talked about is very simplistic, while the first screens are much more detailed, have various critters, and so on.
Overall, this looks like a typical first level; you should test your levels more thoroughly and aim for more consistency both in visual design and in gameplay. On the plus side, I was really astonished when
I finished the first area and ended up on a world map - not many first levels do this sort of thing! And you say it's part of a trilogy... ambition is good!
So keep it up