Very cool, finally a Submachine game I could beat without looking in a Walkthrough, and also very cool that you chose to make a spin-off of the series.
Good graphics and nice ambient sound, like always, creating that dark, ominous and mysterious atmosphere.
The gameplay is good old Submachine, gathering items to solve puzzles, discovering how objects you can interact with affect the environment (in this case it was mostly just the cube thing) and finding your way through to the end. The "reward" of this game looks a lot like a The Sims crystal, but maybe that's just me being nitpicky :P
Obviously, this was a lot easier and shorter than a regular Submachine game, but it's a great spin-off.