Hi!
I was one of the developers of the game.
I agree with you, the portal and time travel mechanism could have been a little more polished and optimized...
You must understand however that we were pretty much on a Time Trial back then. We had roughly 8/10 months to do the entire game.
We would have loved to polish this part, but we couldn't, there was so many things to do...
I'm happy to hear you liked the game nonetheless!