1. Start each level with a few Gatling Guns, and fully upgrade them. The extra damage is worth more than extra guns, even where you're building a maze.

2. Don't place slowing towers early on in any stage. There's no use for them while you only have Gatling Guns. Once you're building more powerful towers, use slowing ones to cluster enemies around the high damage areas.

3. Don't forget you can pause the game! While paused, you can view creep paths and place or upgrade towers, so if you're getting overrun or playing the puzzle levels, this gives you a chance to recover. Pausing will not stop the clock in time trials, though.

4. Despite the tips given by the game, try to avoid needing to place towers away from your maze. Although you may need to catch stragglers at times, a more effective setup concentrates towers closer together to take advantage of status effects, combos, and multi-kills.

5. You can only take a limited number of towers into a level with you. Try to balance your selection based on prices, and scale up the towers you build as the creeps scale up in health, rather than trying to save for a Railgun right at the start of a level.

6. An example of an effective selection consists of the Gatling Gun, Glue Gun, Spark, Hive Tower, Tesla Coil, and the Railgun. In this selection is a cheap turret to be used as a wall, a slowing tower,two mid-range turrets (one short range, on long range), and two powerful, though pricey, turrets (again, one short range and one long range).

7. Although most levels can be beaten without selling towers, being able to rebuild your maze while the game is paused allows you to keep creeps walking round indefinitely. While it's not the best strategy, unblocking earlier exits and blocking the path a creep is on will force it to turn round and go back the way it came, which can buy you some time against stronger enemies.

8. You should always have the Gatling Gun in your loadout. It's great for building mazes even when the damage isn't useful anymore. It's also the cheapest gun, and without it you'll struggle at the start of a level.

9. Towers that inflict poison type status effects don't stack with each other. Don't build radiation towers side by side, for example, because you won't get their full effect.

10. While paused, any towers you build can be sold again for their full value. Use this to try out different mazes - they won't stick until you unpause the game.

1. During Time Trial stages, escaped creeps don't cost you a life. Because of this, it's not worth building slowing towers - the clock is ticking, and creeps with high HP are still only worth one point. Let them escape so that the next wave shows up faster.

2. Cluster highly upgraded towers in one small area where possible, rather than building complex mazes. A creep walking through a long, winding maze is costing you time.

3. Using Fast Forward doesn't speed up the clock, only the gameplay. In a Time Trial, Fast Forward should always be on in order to get creeps through the level as fast as possible.

4. Pausing also doesn't affect the clock, so know your strategy before you start.

5. The Time Trial maps are reused stages, so if you remember the maze you built to complete the map previously, remaking it as quickly as possible may be the best plan.

1. The puzzles are tough! Pause the game after each level to allow yourself time to plan where the next towers are going to go.

2. Remember you can see creep paths while the game is paused, too. Use this to try out different placements for your towers and direct the creeps to the hazards as efficiently as possible.

3. Towers alone generally won't be enough to destroy creeps, but you can still use airstrikes and items if you don't solve the puzzle for a particular round.

4. Creeps will always take the shortest path to the exit, even if it means they walk through hazards on the way. You don't need to line their path with towers to direct them, just block any shorter way to the exit.

1. Try to funnel creeps into as few paths as possible.

2. Focus all your firepower on those paths and hit them with high damage attacks and area of effect powers.

3. You can still use airstrikes and items, but you'll get overrun eventually no matter what, so once you've reached the target number of kills, don't waste additional items on the level.

How do I get more stars?

How do I get coins?

Which towers can target aircraft?

What are airstrikes and how do I get them?

What are elite units?

What do cards do?

Which is the best slowing tower?