So, having played around with the turrets in the current Advanced Level, I have some ideas as to how the Mortar could be upgraded for future Advanced levels if planning to grant upgrades to those turrets.

(While I did use the flak, evidently it worked well enough as it is as I can't think of much to improve it.)

Mortar Upgrades

L2: Boost to capacity e.g. 6 --> 10 rounds fired before reloading.

L3: Cluster Munitions, so being capable of damaging multiple targets in a single shot, although otherwise a net damage improvement assuming most of the clusters hit around the target.


As for some new turret suggestions:

1: Railgun

This could be as either a superweapon like the MLRS (only one per day) or as a standard turret.

Either way it would fit into the high damage, low rate of fire niche that's been lacking from the line up of turrets so far.

If as a superweapon, could have it require manual targeting and have a slow charge-up (45 seconds / one minute between each shot for example) in exchange for being a firm one-hit kill on most targets (Large Tanks or future 'heavy targets' as obvious exceptions)

As a general turret, it would have a slower rate of fire compared to the sniper turrets but packs more of a punch per shot.

Certainly something that would be useful for picking off priority targets or softening up hard targets for the rest of the turrets either way.


2: Laser

Could serve as a combined AA / Ground Turret if a pulse laser design, even if it doesn't do that much damage compared to the dedicated turrets for AA / ground targets. But useful as a stop-gap measure or supplementing a line of turrets with something that can fill in either role.

As an alternative take, could be used as a turret that 'ramps up' in damage the longer it fires upon the same target if using a continuous laser output.