I started going for the achievements after beating the final boss.
Therefore, I recommend attempting it under conditions similar to mine.
Good news, I didn't rely on every gem, so a slight level difference shouldn't be a problem.

Starting Gold : 4550
Gems used in this Archievement : 1526

Trap


Consumable

Trap booster is the most important skill.


Traps used

I haven't studied any other areas besides mines.


Block another way
If you block here, all enemies will rush to railroad .


Let's make sure to level up the freezing trap to tier 4 deep freeze.
And let's set up spring traps to send the enemies back.
If you are short on money, you don't have to install Soul Harvest below.


In round 1, peasants will turn around and run off the tracks towards the freezing trap.
At that very moment, let's use the trap booster on the freezing trap.
From now on, you must use the trap booster on the freezing trap whenever it is on cooldown.

If you have the gold to spare, it would be a good idea to install a black hole like in the picture.
The black hole will bring scattered enemies into one place, making it easy to get the achievement when they're hit by a bomb.


Also, if you have enough money, set up a SpinBlade Trap like this picture.
Spinblades are more stable than freezing traps
because they cannot be passed even by very fast enemies.
From now until the end, you only need to use Trap Booster on that Spinblade.


Sometimes, when the road is blocked or a bomb explodes, enemies will walk towards the railroad tracks.
In that case, set up a harpoon trap and drop them quickly.
If you don't drop them quickly, they will collide with next bomb cart and explode, making it difficult to complete the achievement.
And again, if you have enough gold, add the lower black hole and upgrade the lower soul harvester to tier 4.


If you fully upgrade your Soul Harvester, you will have some gold to spare.
Then, let's install additional spring traps to send back enemies who missed the cooldown of Spin Blade.
In addition, if you install additional traps for proper upgrades and security reinforcement, you can win without missing a single enemy.
One more thing I want to tell you is that the cooldown of traps is reset when you upgrade that.
Therefore, rather than doing a full upgrade just because you have gold left, it's also a good choice to upgrade at the necessary moment.

Thanks for reading.
Good luck.