Make XCOM 2 feel like a different game.
Suppressable Targeting Abilities
revamps the Suppression ability to reduce the range of many area-of-effect abilities, like launching a grenade or spitting a cloud of poison. If you’ve ever suppressed a Muton only to watch him happily blow up your squad, rejoice—you can properly keep his head down now in all offensive aspects. The mod also unlocks the targeting for abilities, allowing you to place grenades and other skills with pinpoint precision, which is a much needed tweak if you’re using to lower your overall damage.
Overwatch Ignores Concealment
is a little change with a huge effect, allowing your overwatch to fire off normally even while your troops are concealed. You no longer gain the bonus chance to hit that vanilla concealed Overwatch enjoys, but in return, you don’t have to jump through hoops to get your stealthed troops to react anymore. As an XCOM:EU vet, this mod is one I really enjoy—I prefer starting fights on the alien’s turn instead of starting ambushes during mine. It’s a definite boost to the player’s lethality from concealment, so consider increasing your game’s difficulty to balance things out.
Additional Mission Types
is a fantastic mod that introduces several new sorts of missions to your campaigns, focusing on defensive scenarios that provide some alternatives to vanilla’s more offensive missions. Defending a resistance shanty town from waves of ADVENT, neutralizing a VIP and holding for an extract, and executing a jailbreak as reinforcements drop in to cut you off are all excellent additions this mod adds to your campaign.
Okay, here's the big one. My favourite XCOM 2 overhaul, which happens to combine perfectly with Additional Mission Types. Instead of wiping out all enemies and rolling in the rewards, campaigns played with this mod require you only to accomplish your mission objectives and extract before being overwhelmed. You will want to extract, because ADVENT calls in reinforcements once they go on alert—at first just small pairs of soldiers, ramping up to full squads of enemies airdropping in to cut you down. The reinforcements provide a great alternative to mission timers as a result; instead of racing a literal clock, you’re racing a metaphorical clock, represented by dropships full of very angry soldiers who will swarm all over you if you don’t move fast enough.
Couple that with only keeping what you can carry to the Skyranger, and your tactical decision making will be put to the test far more commonly than in vanilla. Should you bail out immediately after accomplishing your objective, or stick around a few more turns to grab bodies for research? In Supply Raids, how greedy will you be—happy to head home after snatching a few boxes full of goods, or risking it all to grab all six? While the reinforcements certainly provide a difficulty hike, the fact that they replace timers allows you more options and flexibility, and encourages you to be greedy as you overstay your welcome to grab loot and corpses.
There’s something to be said for racing to the Skyranger with a butt-naked Sectoid slung over your shoulder. Guerilla War’s still in development, but it’s entirely playable now, so if using a Fulton Harness to extract a Sectopod wreck while you hold your LZ sounds like the kind of gameplay you’re interested in, it’s well worth checking out.
Speaking of total overhauls, is a mod dear to my heart. As someone who loves tower and wave defense games, this mod is my dream come true—start with a small squad of rookies and fight off increasingly harder and more numerous waves of enemies on random maps. Your soldiers level up from kills as they would in a real campaign, and as you earn resources from surviving enemy waves, you can hire new troops, unlock new research, and buy new equipment and upgrades.
With troop customization and savegame support and even featuring the new Alien Hunters Ruler aliens, WaveCOM takes all of the fun and progression of a real campaign and sums it up in one huge and endless defense mission—with the nice side effect being that when you eventually lose your entire squad, it’s more inevitable and fun than frustrating.
Recovery Turn System
Finally, while the above mods all pull off some fairly big changes to XCOM, takes the cake for absolutely changing the game. Players of other tactics games or more traditional tabletop RPGs will be familiar with the idea—instead of moving your entire squad at once, and then all the aliens moving next, this mod has each individual unit act in order based on their mobility score, making it more similar to an initiative based system like Dungeons and Dragons. This completely changes how the game is played; no longer can you use your entire squad’s strength to wipe out the enemy before they can act, with combat instead becoming a constant exchange of shots and abilities for each engagement. Whether it makes the game more fun or not is up to you—at the very least, it’s well worth a look for how radically it mixes up the XCOM formula.