Thank you very much for playing!
I agree with the fishing. A chance of 50% / 70% doesn't really feel like 50% / 70%.
It is possible to beat each of the 3 levels, but I think we should have added some kind of tutorial levels. So you get used to the towers / mechanics.
My tip for beating the levels is to place the towers far away from each other and use Tower03, because the AoE is overpowered.