some people might not get the importance of mods in this game,you shouldn't expect to have a lot of fun with this game if you dont play with mods on, because they add so much content and interesting scenarios to the game.
in my honest opinion, it's a pretty good game, you'll probably get a few laughs and good times out of it, also seeing as how you can play with buddies split-screen, but you will definately also rage at it once in a while.
here's the website of the devs and where you'll find the mods (mods are in the fan forums section); http://datarealms.com
i'll list a couple that people should definately check out if they want to play this game here;
there are two kinds of mods that you'll find in the fan forums; mods and scenes. scenes are general scenarios, such as a base assault or an entirely redone campaign. mods are, well, mods. factions, weapons, you name it. someone even made a filter to make the game dark and gritty, and someone made tiberium from command and conquer.
Warhammer 40K imperium of man: a massive mod that adds pretty damn overpowered soldiers and weapons into the game, but not so op that it's no fun to play them, you can feel very powerful with the soldiers, but they're not indestructible, and they're fairly expensive. one thing i should note is that with the soldiers with jetpacks you can do a dash in the direction your mouse is pointing by pressing shift+up.
there's additional instructions for how to make the individual factions other than the standard blue space marines available on the forum page.http://forums.datarealms.com/viewtopic.php?f=61&t=11062
Unitec: *note: it's very important that you download the 1.05 compatible version that weegee posted on page 136 of the thread. otherwise it wont work, unless you're using an older version of the game.*
the unitec mod is really amazing, it adds 3 inredible factions into the game which each have a big variety of weapons to use, it's really incredible how much this mod has to offer. i'd like to note that you can enable hidden weapons in Unitec.rte/Devices/Weapons.ini and change the ones you dont see in the in-game menu to either 1 or 0 (depending on what it's already set to)http://forums.datarealms.com/viewtopic.php?f=61&t=17247
Darkstorm: very cool mod with quite a few interesting devices that will light your enemies ablaze (the fire on them will light other units that walk into them on fire as well) or freeze enemies to death. the warhammer mod uses this fire mechanic as in their mod as well.http://forums.datarealms.com/viewtopic.php?f=61&t=18120
SAW: you should really just take a look at the thread, the artwork that's been done of this is incredible, and it's fairly satisfying to use as well.http://forums.datarealms.com/viewtopic.php?f=61&t=20028
Kettenkrad's wehrmacht: this mod. this. mod. it's nazi and absolutely fabulous. i've seen tanks and artillery as well in this mod, but i think they were in earlier versions of it. it's worth a try to install earlier versions of it and see if they still work. i'd also like to post and additional mod for this one, since it fits very, very well. yes indeed, 'tis undead hitler. (none's post) http://forums.datarealms.com/viewtopic.php?f=75&t=24174
ssl assault: if you're bored of the good ol' bunker breaches, this is a brand new, easy to install scene which introduces 3 new ones (not under bunker breach, but under a new one called ssl assault 1-3) the first two of which being assaults against the coalition with no counterattacks, and the third being an attack against techion with a lot of counterattack once you reach exit the first building you go into.http://forums.datarealms.com/viewtopic.php?f=24&t=29714
Cortex Shock: HOLY COW THIS IS GOOD, i almost forgot this one, it's an adventure scenario that puts you through various fairly hard levels, get your game face on for this one. there is some mod compatibility in this, but it'll be better explained on the mod page.http://forums.datarealms.com/viewtopic.php?f=24&t=31063
SHIELD: Under Siege: this is a scene that requires the Unitec mod i listed, it's a fantastic campaign with 14 levels that each has unique oblectives and hardcore gameplay, very very fun, but be careful not to lose your units, you will instantly lose. the mod is discontinued, but there should be enough content to make anyone happy. i very much recommend getting this mod.http://forums.datarealms.com/viewtopic.php?f=24&t=12807http://forums.datarealms.com/viewtopic.php?f=24&t=17619http://forums.datarealms.com/viewtopic.php?f=24&t=25113
Prison Escape 1-3: i really think you should just start playing this without any other words from me. 3 fantastic missions with an incredible feat of scripting at the end.http://forums.datarealms.com/viewtopic.php?f=24&t=31383
Unmapped Lands 2: this scene is very simple to play, but it can also get very long the longer you play, because the AI gets so much gold that he simply never runs out when he's attacking you. there's a manual in the thread for how to play the games.
and that's it. i hope you enjoy playing with mods, since i certaintly have done. there's a bunch more mods on the forums that you can find, but i'll leave it there.