Focus

=Description=
 * Focus is a powerful tower often compared to Lightning. It has a railgun-like outlook, and fires a constant beam at an enemy. The beam gets bolder and the damage increases as it focuses on the same target, and will eventually reach 5x the starting damage. It's also an anti-heavy-one tower that keeps the high fire rate, in the opposite of most other ones.

=Gameplay Notes=
 * Because of the focus porperty, Focus has both the highest DPS and DPS per resource invested once it has warmed up.
 * The immense amount of damage output by this tower makes it phenomenal for taking down the heaviest enemies. To ensure that it stays focused on the strongest enemies, it is recommended to set its targeting priority to "Most Health".
 * The damage bonus from warming up vanishes immediately when the tower switches its target. Thus, it is beneficial to construct a maze around it that leads a long track through its range without interruptions. If the focused enemy just shortly leaves and re-enters its range, the bonus is lost and it has to warm up again.
 * Around a Focus, the players should generally attack the focused enemy last to make sure the Focus spends more time firing further warmed up on average. If they kill the focused target quickly, the Focus will reset more often than if they skip the focused enemy to instead attack the next in line (or any other).
 * Similarly, the Focus is more effective if it is the only tower assigned to attack the strongest enemies within its range. If other towers prioritize them as well, they die more quickly, forcing the Focus to switch its target and lose its bonus more often. This includes having multiple Focus towers in the same area.
 * Combine the Focus with crowd control to prolong the time enemies spend within its range. This includes slows (from either Kairos, Slow Fields, Slowing Rounds or Slowing Presence), Mind Control Spires, and tanking behavior from players and G-2 companions.
 * The Focus also locks on targets within its range it cannot hurt for some reason, either because there is an obstacle blocking the line of fire, or it has infinite armor (Bobbleheads and Hoverer fronts). A core can also block the Focus laser, in case you put the Focus close to a core. If the Focus gets into a stalemate like this, where it is locked on a target it can't damage for some time, it becomes your first priority as a player to kill this target as quickly as possible, since the tower's effective DPS is 0 as long as it remains in that stalemate, wasting a lot of its damage potential.
 * For the same reason, when placing a Focus close to the core, make sure its range doesn't reach over to the averted side of the core, so it won't get stuck in such a stalemate.

=Trivia=
 * Previously in Sanctum 1 the Focus tower design was used in the Penetrator.