Each difficulty of each level has a unique distribution of enemies, both overall and on each path from entry point to exit. Observe or research the mix of enemies then build the appropriate towers to efficiently use your funds.
- For mostly enemies with armor, build Magic Towers.
- For mostly enemies with magic resistance, build Ranged Towers.
- If you are facing a mix of both types of armor, you will need both types of tower. However, it is common to see different enemy types on different paths, so you may need to build different tower types on different paths.
- For concentrated mobs of enemies, build Artillery Towers.
- For a high hit point enemy with armor like the Dark Slayer, build the highest upgrade level of Magic Tower: the Arcane Wizard Tower with Death Ray that can kill with a single shot.
- For a high hit point enemy with magic resistance like the Demon Lord, build the highest upgrade level of Ranged Tower: the Musketeer Garrison with Sniper Shot that again can kill with a single shot.
- A high hit point enemy with no armor like the Yeti can be stopped by either of these one-shot kill towers. Bosses, though, are immune to the one hit kill upgrades.
- Enemies that deal low damage but are dangerous, like the Shaman, should be stopped with Melee Towers, Reinforcements or Rain of Fire/Thunderbolt. On the other hand, it is pointless to use troops to block a high damage enemy like the Dark Knight or an explosive enemy like the Demon Spawn. The troops are wiped out and until they regenerate they will not be able to do their job of holding enemy units inside the range of nearby ranged towers.
- Plan your use of Rain of Fire/Thunderbolt to kill the enemies that would otherwise cause a breakthrough. Enemies that can heal or create more enemies are good potential targets. If needed, you may be able to bunch up important enemies through use of Reinforcements or rally points to better use the Rain of Fire/Thunderbolt. If you have to use it to stop one or two slippery enemies from reaching the exit, look back at what happened earlier. It's likely that you could have used Rain of Fire/Thunderbolt earlier in a more strategic way to kill more important enemies and leave yourself in a more secure position.
- Use Rain of Fire/Thunderbolt against the strongest enemies on screen right before you hurry up the next wave. The hurry will accelerate your next rain of fire/thunderbolt and give you money. The same goes with Reinforcements.
- The end of each level is designed to be the most intense and tough point. Often it will be the last enemies that break through your defense. When the last enemy of the last wave has passed out of the radius of a tower, you can immediately sell it and buy upgrades or replacements for towers further along the path.