Finally! First time beating the last level. My final unit composition:
5 Strikes and 3 Blazes +120 upgrades
5 Pikachus and 5 Crunches +187 upgrades
14 Toxic Shooters + 140 upgrades
6 Lt Commanders + 160 upgrades
What I am pretty proud of is that I managed to not lose a single life throughout the game. Personally I think the later phase of the game is all about balancing the anti-air splash damage and the anti-ground damage. I sticked to Toxic Shooters for quite some time, then transitioned into Pikachus and Lt Commanders(Valkyries), which turned out to be just about what it needed.
Leave a comment if there is anything that you want to discuss about. Cheers and poker on!