it is build dependent though, some ways way too easy never leak a single thing. levelling up the basic skills seem to be way too effective compared to buying the bigger onces. just a bit of balancing and this would be a nice game, i put 5/5 for your work :D
for level 36 you can use the homing when he starts moving fast around you. and hit him with anything else when he not moving. I used BFG and something else i forgot.