Why not? They're pretty easy to put together, only your experience of level design and your imagination makes it different from all the others, and you'd need both of those if you had a "ready-made" engine anyways.
Maybe there's something more specific you would like from someone to help build your own engine? Maybe a piece of code to solve a bug or something you've not been able to figure out yet?
Try this. I've never played NASUBI 2 Life Force (unless you count "Life Force" on the NES), but here's a basic scrolling shooter engine for you. Has a life bar, lives, enemies, autofire, etc.: