thank you for playing and for your feedback!
The original idea was to have the pickups respawn after a while so the player could switch dimensions again if goes back, but I had some problems trying to implement the respawning in the engine so I had to leave it like that at the end due to time constraints. Changing the pickups into permanent portals would have been a better solution yeah! sadly I didn't think of it at the moment, thanks for pointing it out!