I admire your take on the pixelated take on Portal Flash and, honestly, up to Chamber 8, everything has its challenge and its merits to think portals on 90-degree angles. I will not get into the controls since you have planned to overhaul that, so I omit that from my comment.
However, the portal physics need more work. When I tried to do the infinite-fall, as well as the portal-launch, the speed is inconsistent and when combining both, it's the worst of both worlds with either occasional kill of speed or the portal locations not updated ahead of time, which is a bit of a far-cry from GLaDOS' quote of 'Speedy thing goes in, speedy thing comes out'. It hurt my ability to go past the grill in the aforementioned Chamber 8 where its flaws showed its cracks.
Hopefully, it will become a more enjoyable experience in the Post-Jam updates and not just a tolerable one.