Waves 1 - 10
– Place a Gun Tower on the bottom outcrop and then place your next one in the centre of the split trench.
– Upgrade these two towers, then proceed to place a Gun Tower on the northern outcrop, upgrade it and then place another two Gun Towers on the two outcrops that close the trench down.
Waves 11 - 20
– Your goal now is to build Gun Towers onto the T-shaped embankment that leads off to the exit (starting with the front outcrop).
– You should have all but the one space covered with Gun Towers by round 19. Once these have all been upgraded, this should be enough firepower in this area (for now).
Waves 21 - 30
– Place a Slow Tower behind the Gun Tower that’s closest to the north-west corner of the map (See screenshot above). If you’re using an Ice Tower, then you’ll need to place it just to the right of the Gun Tower due to its reduced effective range.
– Now you should be well prepared to earn enough for a Flamethrower Tower, which should replace the Gun Tower in the centre of the map.
– Focus on upgrading this Flamethrower Tower to level three before round 30.
Waves 31 - 40
– Swap out the north-western most Gun Tower with a Hive Tower as its increased range will really help (as too will its Area of Effect damage).
– Save up to place a second Slow Tower beside the south-western most Gun Tower to catch any units heading nearby (especially helicopters).
– If you have any items on you, keep them ready in case a rogue unit makes it close to the exit.
Waves 41 - 50
– Upgrade both of your Hive Towers as a matter of priority at the start of round 40 onwards.
– Place a Missile Tower in the remaining spot at the far-right of the map to help pick off anyone who makes it this far.
– You can replace one of the two remaining central Gun Towers with a Hive Tower, then focus on upgrading both that and the new Missile Tower.
Waves 51 - 60
– Nothing should be getting through by this point, so it’s now more a case of upgrading any remaining Gun Towers and you can even drop a couple of Missile Towers near the Flamethrower Tower to finish the waves off quicker.
– Not going for Endless mode? Then use your Airstrike on round 60 to polish it off nice and quickly.