Enemy Phase Mechanics Part II

The first discussion can be found here

Basically, I am trying to design a co-op tactical game where the players fight against a common enemy. I would love some feedback on what I've come up with in the last year.

Game Setting
I've modified the game setting. Now the players are mercenaries for hire during a global conflict using mecha to accomplish missions and gain rewards. The players fight against other enemy mecha to obtain objectives, defeat powerful foes, and to survive.

The game is played on square, modular game boards. Each game board has a square grid the player can move across unless blocked by a building or debris. Players and enemy forces can share the same zone (are are then considered in melee) and movement is generally only one square per action.

Enemy Phase
After each player has completed their turn, the Enemy Phase begins. To start, all temporary tokens are removed from the board (Taking Cover tokens, Aiming tokens, etc). The turn starts with a clean slate.

Tactics cards are drawn, one for each player. Each Tactics card has:

• types and number of enemy forces to be "deployed at the end of the enemy Phase
• the zone which those forces are to be deployed
• the special tactic to be performed that round

Tactics would focus on giving specific types of enemies a change in their normal behaviour. Quick enemies could move an additional zone or attack again. Defensive enemies could place a "Cover!" token in their zone to increase the defense of all enemies in that zone. Artillery units could gain an increase to damage. Stealth units could deploy right in the zone with the players. A large force of enemies could be forced to move backwards instead of forwards.
Simply put, Tactics cards would both spawn more enemies at the end of the round and mix up how enemy forces will behave.

After the Tactics cards have been drawn, Enemy Forces are then activated. If the enemy can see one or more players to attack (range of 3 zones), it does not move. If it cannot attack, it moves towards the closet, largest group of players it can see, then towards the closest, largest group of players.
If the enemy would have more than one option to choose from, the players choose the target: the enemy moves one additional zone in this case.
Once done moving, enemies attack. They deal 1 point of damage (per enemy) to the closest, largest group of players. The damage is totalled and then the players in that targeted zone divide the damage among themselves. Each player rolls evasion dice and use their shields to absorb the damage. If damaged too far, the player starts disabling their mecha components until they cannot act any more (that's another discussion all together though ATM).

Each type of enemy force would have something special about them:

• Assault Mechas (cannon fodder): weak and plentiful. Most Tactics cards will affect these guys in addition to other mechas.
• Infiltrators (stealth and melee): they cannot be targeted by ranged attacks and cannot make ranged attacks. Tactics cards will deploy them on players instantly before attacking and occasionally give them an extra zone movement.
• Artillery (AOE damage): ignores Line-Of-Sight (shoots over buildings and debris) and the damage is applied to each player in the zone. Encourages players to split up. Will not attack if an enemy unit is in that zone.
• Guardians (tanks): require more hits to kill, must be targeted before any other enemies in its zone are killed. Tactics cards will have it provide cover for other mechas in the zone, effectively making it very difficult to kill anyone in that zone.

After the enemy forces have been activated, the reinforcements will be deployed. Tactics cards will list zones 1 to 5 (1-2 being very common, 3-4 being uncommon, and 5 being rare). If two or more Tactics cards share the same zone, the reinforcements deploy together to form a bigger squad.

After all reinforcements are deployed, the tactics cards are discarded and the player turn begins.

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that's what I've got so far. What do you guys think? Is it simple enough, or too confusing?