Oh yeah, bonus objectives do make the game much more difficult. But they're optional at least. There's also the hidden 100% gold bonus objective. I've hidden it so it's not a frustrating bonus objective, but just something to reward the player if they do go through all that trouble.
I prefer not to force the player to do anything. I'd rather give the player as much freedom as possible and giving the player more options over time.
Here's my current progress with the level editor:
It is just a graphical front for the text level. Feel free to share your text level, and I'll post a play-through of it here again, so you can either tweak it or if you're happy with it, I'll add it to the next update if you like.
I will try to release the next version with the completed level editor this weekend. So you can also wait for that update if you prefer. Although the level won't be playable through the level editor yet. I want to save that feature for the full version. I'll release the full version alpha within a few weeks. I'll send you a key for it ^^