Sentry-Pack: Engineer wears a level 1 sentry gun on his back. The sentry gun can only shoot behind the engineer, and removes the engineers ability to build sg's. Making the sentry gun portable slows the engineer down and can overheat
Pros:
Attacks pursuers
Increase Battle Engi potential
Warns of flanks by the firing
Non-missing damage
Cons:
No SG
Can only shoot 90 degrees behind the engi
Doesn't have a knockback
Slows engineer to demo speed
Sentry gun overheats if shooting 5 seconds straight, for every second shot, takes 1 second to cooldown. Must do a complete cooldown if shot for 5 seconds
Wall-Walker: Builds a robotic gun that walks along a wall in a single direction (Set-on build) that will follow the wall until death or out of metal. The walker can go around corners and shoots at 1/3 the speed of a sg but can move while shooting. Loses metal over time and when shooting. If no shots are made, survives for 1 minute
Pros:
Fast build speed
Good for attacking inside buildings or preparing/holding capture points
Allows you to attack without being in the line of fire
Cons:
Enemy SGs obliterate them easily
Lower hp and dps than sg
Can't upgrade
Dies over time, cannot be repaired
The Engi-box: On death, the engineer drops his toolbox. If a sentry-gun is not currently built, it will construct into a sg after 5 seconds, normal build time. If a sentry-gun is out, the box will explode after 5 seconds. This prevents an engineer from upgrading a sg to level 3
Pros:
Gives engineer a chance of retribution with a free sg
Engineer can rebuild if sg survives if he returns to it
Explodes to prevent players from staying near the box expecting a sg to be built
Cons:
SG is defenseless during build up
Loss of lvl3 SG
Explosions from box are on a delay
May die in an area SG can't be built