I played three runs. I liked it a lot! If you have some free time, try it!
1) The first time you play the game, every player plays the same tutorial campaign. It shares the same missions, maps, and enemies. The next runs have different missions, maps and enemies.
2) When your 3 characters are defeated at the same time, you lose the campaign. Your next run will unlock a new npc-character in your HQ, like Rumi, that enables more options to improve your characters, weapons,...
3) Each mission have a main and optional objectives. These objectives ask you to defeat all enemies, a number of them, don't suffer x amount of damage or KOs, survive several turns, scort Rumi to the exit or destroy a convoy before runs away.
4) After several missions, a mandatory boss will appear. I have not defeat him, so I don't know what happens next.
5) The game tells you that Tarma is unlocked after defeating the boss.
6) Each character have his own skills and two weapons. The main weapon has unlimited ammo, but the secondary not and you need to complete missions that give ammo to refill them. Marco buff himself or others, Eri is all attack and movement, Fio can move allies or enemies, heal, shoot far away or improve the defenses. Seems that you can unlock several starting skill sets for each character that changes their play styles.
7) Your characters have hp, energy, cover and movement shields, active and pasive skills:
-The more you move, the more energy and movement shield you get. This is a really cool mechanic to simulate the run & gun gameplay from the original games.
-Movement and cover Shield points reduce all the damage during all the turn. These shields are really important because your characters have not a lot of hp.
-The energy you get by moving is used to activate non-pasive skills.
-You can get cover shield points moving next to cover tiles -these tiles will be damaged with each attack they absorve until are destroyed.
-If you attack an enemy that other of your team members have in range, you will make a combo attack called sync.
-Guns only hit enemies at range, same height and without other characters of big obstacles between. Grenades ignore height and obstacles.
8) I found one hostage in a mission, but I could not rescue him. I don't know what they do.
9) Some missions expands their map layouts after a number of turn. It's cool.
10) The skills have three tiers, you can upgrade or replace them. Your character have his own skills, but your weapons have a number of slots to add more skills and effects.
It's a limited demo, so a lot of options and 4 of the five campaigns are blocked. Also, the game have some visual bugs, have a small amount of music, and it lacks many sound effects.