Hey, Maybe I'm not quite your target audience but...
I played your game for a few minutes then felt, bored isn't the right word but didn't know what I was trying to achieve. I had no goal. After that I left it in the background to see what else would happen.
In the game Magic Archery there is always a new interesting goal to get. It starts off as getting stronger then changes as things get unlocked. The goal changes keeping it interesting.
In Wizards Tower I felt compelled to grow the tower. A fairly simple goal but compelling enough that I finished it.
The UI was good, clean, crisp and easy to read and understand. It took me no time at all to figure out what I was meant to be doing.
GL