Dark Void
57 Achievements
1,250
15-20h
Spirit of Tesla
Upgrade a weapon to stage 3 in a survivor mission
25
How to unlock the Spirit of Tesla achievement in Dark Void - Definitive Guide
You can do this in either the Battle of Ghen Crag or Abyss Canyon Missions, just earn enough points to perform two upgrades to the same weapon. Very easy. The trophy will unlock immediately after performing the required upgrade.
You can upgrade either between waves or at the weapon locker on either map (it's marked on the mini-map and shown on your HUD). To make this one even easier, make sure to not turn on the 'Low Tech' modifier since it increases the cost for upgrades (but remember 'Low Tech' is a good option when going for high scores). However, you can also just get this one while doing your 4.5 million run in Abyss Canyon, since I recommend upgrading your jetpack twice for that.