Had a quick go on this earlier and have some initial thoughts
They unlocked the new grenades from the get go no missions to get them just pay the cost and materials and they're unlocked
Mincer grenade quite fun
The new plague disposal mechanic is interesting but annoying single player
you have to spray the plague spores with foam then hoover them up. These take two different tools which are called down from space and then equipped but are not permenant weapons you can drop them. With a team where you can have someone spray stuff and someone hoover it would work fine but solo it gets awkward.
They allow bosco to do the hoovering which is good so you just equip the foam gun but to signal bosco to hoover up you have to do the normal aim and command which means you drop the foam gun so you are constantly picking it up and chucking it down and also when ever enemies appear you aslo have to chuck it to use guns.
Plus the plague infected ground slowly builds up a sort of poison thign and when you have to keep going to get the foam gun after you've thrown it into the stuff for the fifth time it gets annoyign
Still some fun new stuff there just a few niggles I wish they'd done a different way