Would it be practical to use Spring to make a game like Freedom Force?

Off the top of my head, things that Freedom Force does that I'm not sure Spring supports:
* Using up "energy" to make attacks.
* "Overpowering" attacks so they do more damage but use less energy.
* The ability to pick up objects and either throw them or wield them like clubs.
* The RPG-like ability to "level up" abilities through the expenditure of character points during play.

In short, Freedom Force is an RPG-like squad-based RTS rather than a large-scale RTS like TA.

Is this the sort of thing that could be done in Spring via a mod or would it require significant code changes?

Thanks.

Well you dont need anything to change on the Core engine But
you need to get somehow lua things to work because the Engine doesn't support that native.

Spring already got Energy so 1 point less to solve.
Overpowering could be faked with "Dgun"/On/Off Button.
Might use some "Hacky" Cob/Lua unit script.
It is unavoidable that Lua is needed for this.
Maybe there is already some Gadget scripts for it already which is close to it that does similar things but i am unaware of it.

The bigger issue I see would be making a campaign that stretches across multiple missions.

Zwzsg already has restart spring with a new map etc secret sauce ( warning: secret sauce may not be so secret )

do not know Freedom force, yes on all that questions.

if you just want to save "mission 5 is completed, hero is at level 12" then you could just read & write savegames.
ie spring tanks saves which battle you have completed (and if you win 3 different battles you unlock a lame minigame)