I'm looking for an old pc game but don't know the name anymore?

I've been looking for a PC game that I played years ago. Unfortunately there's a little problem… I don't know what it's called. In the game you run around with something like a pulse cannon and have to shoot at floating cubes that contract for a few seconds after a hit and fall to the ground. If a cube touches you, it will throw you away. You also had to climb a tower with different platforms and different numbers of opponents. It is a game in which you have to think a lot and be strategic. In my youth I looked for it xD. Would be great if one of you could help me. Unfortunately I have no pictures or the like and do not know in which year it came out. Also no hints since my laptop or the hard drive on which it was long ago is no longer there (completely over). I'm really grateful for any answer.

Cube or portal?

can you describe the graphic in more detail?

Kula World? Was also my favorite game PlayStation 1.

Neither the cube nor the portal, but in terms of graphics, the cubes came across as in portal unless there was any other version of portal or I can only imagine that as a training level. The cubes flew or hovered by themselves and I think I can remember a robot-like voice that came from the cubes that were talking about 'find him, get him, kill him, whatever' or something but I can only remember it in part It's been a while. But thank you for your reply.

Unfortunately not, but the dice flew towards you and tried to catapult you from the tower.

On this forum similar games like Portal are called, vlt. Yours is there

https://forum.hookedmagazin.de/thread/26-kennt-ihr-spiele-die-so-%C3%A4hnlich-sind-wie-portal/

Super nice game 👍