I got a score of 460 first playthrough. I don't think I was very good at strategising as I ended up with 2's swapping to the righ then back again. Woops.
I really enjoyed this very much. The machanic is clear and simple to understand but challenging to perfect. The clean aesthetic is really nice and the music added to the background nicely.
It would have been good to have volume sliders or settigs as the music was a bt loud for me, and also having the default game widow set to 1080p is often not a good idea as with the browser search bar and your taskbar portions of the game are cut off unless you go into fullscreen. It's a good idea to build for 1920x1080 and set the browser widow to 1280x720 with a fullscren button. This means it will display correctly at the right aspect ratio even without fullscreen.
A great game, well done.