I really appreciate all the positive feedback!
The game, I must say, is more difficult than I would have liked it to be, and perhaps a simple tutorial or a less steep difficulty curve between levels would've been nice.
I actually considered the return mechanic you stated- the "pacman effect", where the player loops back to the origin, but I completely forgot to actually implement it. There's another mechanic I did have though, the small yellow dot next to the ship that points towards the star, but it isn't referenced in the controls or anywhere else.
As for the lack of game engine, I mostly did it for the reasons you pointed out. It was a great learning experience, very rewarding, and I personally find it very fun to create a game from scratch.
Once again, thanks so much for playing and reviewing!