When I was first looking at the jam's theme, I was struggling trying to figure out how to not essentially make two different games in one as I didn't think I had enough time for that. I applaud you for doing exactly that and doing it well.
It was a lot of fun trying to sneak around the guard in infiltration mode. However, defending was a bit too easy. I just stayed right next to the golden cube and angled my view to catch all the white cubes coming at me before they got to it. I cheesed my score up to over a hundred doing this without moving. As @ccallahantow said, it would be a lot more fun if the golden cube moved or if the white cubes had a bit better AI than to just run straight at it.
Also, the opening cinematic and menu background were awesome!