With the release of Locked Projectiles, one thing came to my mind: Tower Defence.
Zombie suggestion:
Sure, we could do a single line with a guy at the back doing a constant setZombieTarget, but where's the fun in that?
What I suggest is being able to name bricks or placing special "waypoint" bricks, then naming [pathname][number] in increments (with the zombie spawn being the first and the possibility of naming multiple bricks with the pathname so they all follow one side), such that they follow the points until there are no further bricks where which they either go on freely, or continue straight forward or get killed. There could also be an option for the zombie brick to spawn multiple spawns so we don't spam up the place.
Locked Projectile suggestion:
And what comes with all tower defence games is tower upgrading. There could be a few events to modify the amount of bullets fired in burst, automatic etc, so it'd be something along the lines of modifying the locked projectile events, hopefully with the use of a GUI as in RoB, earning points.
Hao2TD: Well, the "build" time for the towers will be actually hand-building the towers and placing bot triggers around the paths for limited range. Well, that's all I can think about for now. Hope someone makes this.