Yeah, I like Construct 2 because it clicks with the way I think better than most of the other tools.
You're probably right that you are overthinking a bit, but it takes time to wrap your mind around this stuff. In my experience, one has to experiment a bit and break a lot of things before it starts really making sense.
If you used Bunnystep, you wouldn't be creating all of the platforms. That was just what my example did to show how autogeneration of a level could be done.
To blow your mind a little more, I present BunnyRun:
Yes. BunnyRun. Heh, heh. It is a combination of BunnyHop and BunnySteps, more targeted to your actual case. There is one layout for the levels, with different backgrounds depending on the level number. Also the number of points required to get to the next level gets higher each level. (the points are sort of like your monster kills needed to get to the next level.)
Also, between levels there is a store level with its own event sheet. The player does some stuff and then clicks a button to go to the next level. If there are no more levels "The End" is displayed instead of the store, but you could display the store again, or whatever you want.
There are comments in this one that may help you understand it better.
As far as the problem you were having with BunnyHop first level, I think you may have run the game after going to a different level, or perhaps I saved it that way. Go to the Level 1 tab and then run the game and see if it is better. You can specify the first layout in the property panel for the project, but when you click the Run button inside C2 it starts with the last level which is very useful if you just want to test that level, but it can lead to some odd behaviors.
re the txtMessage, you asked where the "complete!" comes from and what does it do?
It is just a string. You could just as easily say " finished!" or anything else.
txtMessage "set text to "Level" & LevelNumber & " complete!"
will just display "Level 1 complete!" at the end of the first level,
"Level 2 complete!" at the end of the second level, etc.