The first game is like a Sci-Fi Gauntlet with missions on planet to accomplish before you can evacuate. You can outfit your soldier with different weapons and strategems, as well as a perk.
Choosing a main weapon, of which there are many, will either make levels easier or harder based on the enemy types you are going up against. Weapons and Strategems are also upgradeable by finding samples on planets which is your upgrade currency
For example, if you are going to a Snow planet, then you would want to choose the boots perk so you don't have a penalty to movement. On a Desert planet you might want to choose a grenade perk or shield. You can choose your loadout to be more of a support role, a tank or a specialist that will coordinate with your team to shore up deficiencies in their load outs.
There are weapon systems with Strategems, that is the key command you enter in like the Konami Code which causes your command ship to orbital drop resources like ammo, c4 or rifles. Some of these weapon systems work well with a partner in that your partner can carry the ammunition and you carry the weapon, they can then resupply you which is much faster than reloading your weapon on your own. However, if they die and leave behind the ammunition pack and you don't pick it up, you now have a useless weapon. So there is strategy to consider as well as teamwork.
You want to keep your team alive, so you memorize the key command to call down your dead compatriots.
There are also defensive and offensive strategems. Missile barrages, bombing runs, tesla towers for point defense, napalm fire walls, razor wire, mechs to pilot, troop carriers, tanks, etc...
The game does a masterful job of organically causing you to work as a team and it does it with minimal direction. The way the game flows you naturally are looking for each others backs. I jumped in the game after it had been out for a long time, last year and I gained so much knowledge just by playing with veterans in the online community. When you have a level 50 guy drop in and just show you how it is done, looking at his gear as well as playing with everyone in between, you learn how to play the game at your current level as you work to getting those higher tier weapons. All the while you are learning how to play, how to set up traps, how to take on the tougher enemies and mobs.
I only got as far as level 27, that grind to level 50 would take me another year as I don't play it every day, however I have lost track of time when the lists are full of people. You can still regularly find groups to play with, of course some times of the day are more populated than others. There were a few weekends when everyone I was joining up with were from Japan.
Nothing feels more awesome than dropping into a game where there is a sole player bleeding out and you just come in and wreck shit, save his ass and you both go on to complete missions. Then the odds start to stack against you and you have another player drop in, you three are bolstered and the comradarie builds, then a fourth comes in and you dominate the planet.
No other game has brought this type of experience in a coop way that I can remember. The missions are short, but the action is so frenetic and when you are bleeding out nothing raises your spirits more then when someone drops in and saves you.
Oh yeah, Team Kill is a thing. Every weapon will kill your buddies including yourself. It's funny, don't take it too seriously. Also, don't go out of your way to grief in a game.
