Bloodling is a Super Fast Fiend

As you can see when you have fiends close to the gate and you do not enough hearts to save yourself so there are more than one solution and to know the solution would be in the second attempt when you are to enter the new level and to try it again.

For me Bloodlings is a very dangerous fiends and although it didn't have armor or any defensive style like attacking towers and their HP is low as it is only 200 but these ones are extremely fast with speed of 125 and there are annoying thing about them also that they come in large numbers and groups.

Best Solution for them is not buying towers as epic or rare from the market but the solution with a common tower that are with you in the battle and this one is Gloom Owl that are the first tower that you have used in the battle and in first level.

Gloom Owl is best Solution for Bloodling but with some conditions to eliminate them all and first one is to be upgraded and second one is add two towers of Upgraded Gloom Owl close to each others and in this case those bloodling would fall in the trap and no one could pass from them.