Looked pretty, disappointing.
While the game looked decent, some things were highly unnecessary, and the game in general is very disappointing after the first few levels, oddly right when multiple options pop up. Gee I wonder why.
Well, as the game progresses, I found I never used the question mark space. It didn't serve a purpose that the x didn't do better. While yes, if I x out a whole row, which is a nice feeling and I see only a straight row with 4 potential blocks and a line of four being needed, I'll easily assume that I need to put that row in the 4 row. However, the game fights with me, and it won't let me do possible ways. I ended up having to just give up a lot of levels to get a new one because I simply couldn't find the right way. While I'll admit, it would be very hard to accomplish a system where it would allow any set way as long as it worked, it's what this game needed.
As William94 says, it's like in a math test.
I can solve for x by subtracting and adding like factors, or I could just look at x + 5 = 7 and know x has to be 2. However, what this game is like is I have to show work, using a more complex math pattern that I don't know and it costs me the math test. That's completely unfair and poor design in my opinion. This is basically what this game boils down to.
I'll admit again that the beginning levels are straight forward, only one logical option is open, but even in those, level 4 and 5 I think I had to use a common tetris piece that looks like a squished-together z, and I couldn't find the right fit until a few trial and error clicking arounds that eventually led me to the answer. In minesweeper, you can click anywhere you want, but if you click a bomb, you die, you don't know where these bombs are until the very first click. If minesweeper had no numbers, it's what this game essentially would be. I think You understand what I'm trying to say by now. I can tell you're good at game making, just try a different subject or work out the major flaw in this game and you'll be golden my friend.