Thanks, your feedback is really constructive! I agree with your comment on the portals. I had been pondering about how to present them exactly for quite a while. Personally I like that you can't see the portal pairs directly, because that opens up a few level designs. I will experiment with this going forward, and try to communicate which portals to take through my level design. Thanks for sharing your thoughts on that :)
Only thing I want you to know is that there is a hint on the screen to help you solve level 8. Let me direct your attention to the "18" near the flag. I'd like to hear if you can get it with that information!
I also completely agree with you that the different mechanics are introduced much to quickly hahah. That is mostly because I wanted to show off as much from my idea as possible for the sake of the game jam. The finished game will be much slower pace.
"I liked the game and played it to the end" --> Puts a smile on my face ;)