This is a nice-looking level, I must say. I don't think the white parts exactly match the rest of the tileset though. It's a minor gripe, however.
There is one big issue though, that I think you should fix asap:
On screen x999 y1000, after obtaining the high jump powerup, you are able to jump off the edge of the level into a void. You should add another screen there (at x998 y1000) to fix that.
Once you fix that issue, I will conduct a full review of the level, as simple and small as it may be.