Easy "Beat all levels on Hard"...
	Various Steam Achievements...

The in-game leaderboards for this game seem to be glitched, so if you're not sure what levels you've beaten on hard, the best way to tell, is to check the stars on the mission start page. Also, when you've done the last level on hard, (or normal for that matter), the achievement doesn't pop and it was only after replaying the first level again that the achievement then popped. As for actual advice on finishing the levels on hard, I found it worked best to focus all my upgrades on the tesla tower, to increase the power, lower the price, etc. There were some levels where one fully upgraded tesla tower was literally all it took to beat, as it targets all units. So work towards building one as soon as you can, using the builder bots tricks initially to defeat a few mobs and raise the scrap needed. Buffing the builder robot also helps in this regards. It's not necessary to 5 star all the levels for this achievement, so if you do let a few slip through, don't bother restarting.

Complete the indicated task to unlock the achievement.

Achievement	How to unlock
Arachnophobia	Do not allow Swarmies to spawn in a level that has Swarm Mothers, and beat the level. This must be done on atleast Medium Difficulty.
Beat all levels on Hard	Beat all levels on Hard.
Beat all levels on Normal	Beat all levels on Normal or Above.
Beat Level 1	You have completed Level 1.
Beat level 1 no towers	Beat level 1 without building any towers. This must be done on atleast Medium Difficulty.
Beat level 11	You have completed Level 11.
Beat Level 14	You have Completed Level 14.
Beat Level 17	You have Completed Level 17.
Beat Level 21	You have Completed Level 21.
Beat Level 5	You have completed Level 5.
Beat Level 5 without waypoints	Beat level 5 without allowing any enemies to get to a waypoint. This must be done on atleast Medium Difficulty.
Beat Level 8	You have completed Level 8.
Keeper has reached level 15	Keeper has reached level 15.
Keeper has reached level 20	Keeper has reached level 20.
Keeper has reached max level	Keeper has reached max level.
Kill 100 bots with your Keeper in a single level	Kill 100 bots with your Keeper in a single level. This must be done on atleast Medium Difficulty.
Max City	Fill all the slots of your city.
Max Factory	Fill all the slots of your factory.
Max out a tower	Get a level 6 tower.
Sniper	Kill a mob in the final hex, and beat the level. This must be done on atleast Medium Difficulty.