As requested I will try to show you as best I can how I finished this map on Easy mode.
First off I've got all the skills now but it should not be neccesary. Just makes sure you got the tower skills and the oxygen skills maxed as those are the most important.

At the start I upgrade the oxygen generator once. I did not find a good opportunity to max the oxygen generator but there might be a gap somewhere, this defense is far from perfect and I leaked 10 mobs and finished it with only 2 tablets this time. So if you want to finish it with two tablets you will probably need to use a health boost but that's fine by me.

In the top middle and lower middle you can sell those barricades and put a few cannons there and upgrade them. I keep my hero at the start of the top spawn and therefor I will upgrade the lower mid towers first to compensate for this.

In the first screenshot you can see the first towers I've built.


You will want to get those melee towers upgraded fast and after that I placed some tesla's on the corners.



The next screenshots will gradually show how I improved on my defenses during the waves and I hope this will be enough for you to finish the map. Getting the platelet golems out soon after the next waves is very important.





Around this point I will be upgrading my booster towers to boost the tesla attack speed. I upgrade my ranged boosters once with the 300 upgrade as well.



Don't forget to always manually target those healers so they die fast or they can become quite troublesome.





At some of the bottleneck areas I upgrade some of the cannon towers with 1 or 2 critical chance upgrades. You will need to keep an eye on which areas might need some immediate attention and those upgrades can help quite a bit then.





Good Luck & and if you found this guide helpful please rate it up :)