Wow I really love this game. Like many people I struggled to get past the first minute, but after reading your guide it felt trivial =).
The graphics and controls were really responsive and the bullets had a nice bouncing feel to them. What is impressive about this game is that the geometry of the level design actually matters a lot. It may seem like the hour hand is useless, but it actually acts with the minute hand as a "reservoir" for the diamonds so you'll always have some easy points to pick up when you're on the left side of the clock. It also helps to shoot past the second hand as it's coming toward you so you don't miss out on energy.
Another thing I really like about the game design is that even though it feels like the same loop every minute, your actions in the past minute actually ends up changing the level every so slightly. So it's 99% similar for the next minute except one thing is different, and over time these small differences add up to the point that the level becomes totally different, even though the change is so gradual the player barely felt it. (This is sort of like the minimalist school of music, which I also really love)
The only slight problem I have right now is that even with the gradual changes, the gameplay is a bit too linear (in the first minute you MUST unlock tick 0, the next minute at tick 1, and so on). I wonder if there's some way to design the game so that in the first few minutes you have to unlock something really far from the minute hand, like tick 35 or something. But due to the time constraints this is all very understandable.
Overall this is a very sweet game with a lot of design potential! Félicitations!