Thanks for the replies. Yes my levels are mostly medium to hard. This level was easy in the beginning without central four tiles, but I added them to make it harder. It is because there are lots of easy levels for PI and new ones are coming almost everyday, and they are good levels mostly. I am trying to do levels which are different and that often meens tougher. I do not intend to make hard levels, it just happens. I have an idea and try to make a level, not knowing what will come out. For the last 3-4 hard levels I didn't know even if they have a solution until I solved them myself.
dear the_s, you asked for feedback, here it is: sometimes when i try to solve your levles i have to think that the_s did the level just for himself. you're a stunning good player and a stunning good designer, why don't you use your enviable skills to create levels also for us mediocre players?