Launch three grenades for 3x80% damage.
Drop a trap that explodes for 300% damage. Hold up to 15.
Launch four heat-seeking harpoons for 4x250% damage.
Drop a turret that shoots for 3x100% damage for 30 seconds. Hold up to 2.
Drop a turret that shoots for 3x100% damage for 30 seconds. Hold up to 3.
- If the player is quick, the engineer can jump off a ladder/rope and drop a Mine or Turret before grabbing on again, allowing for safe damage. They will typically fall to the ground below, but not always. This also works off ledges: hop out, drop a mine/turret, then quickly change direction to land back on the ledge. It is possible with no jump or move speed boosts, but much safer with them.
- Tri-nades don't detonate on contact with walls, although they detonate after 4 bounces (or on contact with an enemy). They can bounce off of walls to hit enemies behind the Engineer or from odd angles in a vertical shaft.
- Soldier's Syringe will speed up the time between the engineer being able to shoot again.
- The Engineer does not lose momentum when laying mines, making them an excellent tool for "kiting" (attacking enemies while fleeing to stay out of range of their attacks).
- The detonation is treated as a hit, procing on-hit items.
- The Spirit artifact can make mines very hard to use. Any fast-moving enemy can trigger a mine but move past it before the detonation. This can cause an entire field to go off with no damage done. Jump over the enemy so it changes direction on top of the mine; this should provide enough time for detonation.
- Improperly clustering mines can reduce their effectiveness. An enemy hit by a blast may be knocked past the next mine, causing it to detonate without dealing damage.
- Has good range and tracking, easily able to hit enemies in hard-to-reach places. This saves the Engineer a lot of travel.
- Stops all horizontal movement of the Engineer. This is most detrimental, requiring time to fire it while remaining safe. The Engineer can jump at any time while using it, so vertical dodging can work well with Hopoo Feather or Photon Jetpack. It can be useful, too, if performing tricky jumps, by using it to stop the character from overshooting a platform. Spirit Artifact in the Temple requires precision to get, and this effect provides that.
- Engineer can safely use Thermal Harpoons in a group of enemies by laying two mines, and jumping while activating the skill. This will give them enough time to resume running at a safe distance.
- Attack speed affects the time it takes for the harpoons to fire. Stacking Soldier's Syringe reduces the time Engineer is immobile.
- Their attack speed scales with the engineer's current attack speed, including attack speed modifier items.
- Turrets can draw monster aggro. They seem to have an aggro priority equal to the player, making them gain the player's aggro if the enemies lose it.
- Turrets can be stacked with mines to aggro Magma Worms and Wandering Vagrants quite effectively.
- Sometimes laying a Mine or two near the Turret will redirect monster aggro. This is a great tactic for distracting large groups of mobs, including bosses; this is especially good against Providence, as an Engineer can place a turret, stand back and batter him while he hacks away at the turret.
- They are not invulnerable, although they sometimes seem extremely tough and other times die very quickly. Putting them in a slightly hard-to-reach spot, such as just past a gap in platforms, will allow them to aggro without actually taking damage. Try using them as a meat (metal?) shield, with mines and grenades stunning enemies.
- As the Turrets will conduct electricity, shocks from Overloading monsters can hit the player through them (if they were just deployed, for instance).
- Items such as Brilliant Behemoth will NOT affect turrets. They will just continue to fire normal bullets.
- Any on-hit items are amazing since the Engineer shoots 3 grenades with his basic attack.
- Alien Head will generate Turrets and Mines faster. However, Gigantic Amethyst (Use Item that resets cooldowns) will not give an instant turret or mine when it's used. The Wicked Ring does not help produce mines or turrets any faster.
- Engineer benefits greatly from items that give him additional time in the air. Thermal Harpoons can be fired safely while airborne and staying in the air for a second or two will often cause enemies to clump up beneath the Engineer, making for maximum mine efficiency. Mines can be dropped while airborne as well, so getting a Photon Jetpack is highly effective.
- Dynamite Plunger is a fantastic item for the Engineer, especially at low levels, against Magma Worms/Overloading Magma Worms and the Cremator (and most other bosses), as they can one-shot most of them with a good pile of dynamite and the right timing.
- The damaging trails of Fireman's Boots and Burning Witness can work well with mines for kiting.
- Sticky Bomb - Engineer: Detonate 15 Bounding Mines within 5 seconds.
- Concussion Grenade - Engineer: Kill a boss in 15 seconds or less.