I love the look, but had no idea why I was losing or how to even go about winning until coming here to read the comments. Needed a bit more onboarding into what I'm supposed to be doing - which I'm sure you would have accomplished if you had more time. Nice effort, anyway! 

I managed to get to the portal! I think I figured out the big asteroid pattern (you have to pass directly through it). I thought I had the small asteroid down by being super far away from it, but sometimes that seemed to not work. I thought maybe it involved movement? Couldn't quite figure that one out. The medium asteroid, was it something to do with passing close to it but not through it? I'm curious what the right answers are though! 

Overall, I feel a few small changes could help this game be really fun!
1) Visuals: Personally, I liked the visuals (I enjoy the pic8 aesthetic a lot). I think if you added some scrolling on the stars in the background, and some animation on the portal, it could help everything pop! I haven't done any pico8 yet, so not sure how difficult those 2 things are in that environment, but in my head they don't seem too bad and I think it would help elevate everything visually :D
2) Gameplay loop: So correct me if I'm wrong, but the main gameplay loop seems to be about maneuvering your ship through 3 basic patterns/obstacles and the complexity is initially in figuring the patterns out but "endgame" would be having to resolve the patterns being stacked w/ each other or in following closely behind each other. Assuming that's correct, I think that figuring the patterns out could use a little more guidance in the game somehow. Maybe like a tutorial level per asteroid where you have to try to pass one asteroid of each type, one at a time and you get 100% confirmation that you solved the pattern correctly. 
After that, you could have levels that get harder (or if you want to spawn rng asteroids, the levels could just get longer or have more asteroids possible to spawn or something). Because I do feel the core loop itself is a good idea once the patterns are discovered! 

Another possible idea would be maybe the sensors are broken still, but they sporadically ping to reveal a little of the real pattern, but you have no control over when it pings or how much is revealed, so after a while you'd get the pattern down that way? Not sure, just spitballing ideas!

Overall, I do think the core idea is good though and totally understand running out of time w/ it being your first pico8 game. Impressive to have produced this much in 3 days! Hopefully this feedback is helpful and not just rambling nonsense haha XD