I really liked the demo itself and I particularly liked the use of different types of cubes.
The jank wasn't too annoying either as it was only ever minor issues.
I did however find three game breaking glitches. The first one just saw a small cube go at light speed and never return. The second saw the flat cube go through a wall.
The third happens if your standing in a specific location and place the secondary small cube on the secondary large white space. When the large cube appears the play is locked in place.
Other than those it was rather fun for me to play and while I had to reset a few times I was engaged enough to actually complete the demo