My feedback: Very well polished game, with a slick seamless and intuitive user interface. The interface's layout and its graphics are quite professional in my opinion. The background music is effective and unobtrusive, and fits well with the overall "casual, just relaxing" atmosphere of the game. The graphics of the game itself, apart from the menu's interface, are slick and pleasing also. The full-screen mode worked flawlessly in my browser also without any glitches or hiccups.
I don't really have anything negative to say about this game, or much to say in the way of improvements that I can think of. I might suggest having several soundtracks available which the user could select from, or even a random "shuffle" feature for multiple soundtracks. This would add more variety and longevity to the game, maintaining the user's interest / engagement. And, of course, more additional levels would always be welcome, but for the purposes of the Game Jam, I tend to think that 10 levels seems to be just fine. Maybe some color-themed groups of levels (blue, yellow, green, etc.) could be easy to implement and would add more simple variety to the game. I eventually got through all the levels, but not without some failed attempts and some rethinking to navigate through them!
The game adopts the "Blocks" Game Jam theme quite well. The blocks play an integral role in the game, and are not just a surface shallow addition to the game's theme and mechanics.
Nice to see an AGK (AppGameKit) produced game - that's the same BASIC dialect and system that I am learning and it is capable of producing superb results in many different game genres. I am not affiliated with AGK or paid by AGK in any way; from my own use I just think it's overall an excellent development system with a solid, comprehensive BASIC dialect included.