Thanks! I'm glad you had fun with the upgrade system and the different areas!
The map does have an icon for the portal once you've found it (a purple dot) but it can be a bit hard to see. I wonder if it would have been a good idea to add an outline around it for better contrast.
Good call about the upgrade management - we put it in the bag just to make it very robust so you don't lose upgrades in an edge case, but I did run into that problem once myself during testing.
Glad you liked the ninja, I was worried the mechanic wouldn't be clear but people generally seem to enjoy the fight after figuring it out.
After the fourth boss, the flower, it eats you and you end at the title screen again. Your build gets consumed to be used at the third boss during the next loop. The loops should be playable, they worked fine in editor and Firefox web build, but we had been fighting a camera but that I thought I fixed but maybe not?