A classic TBS game that I bought for nostalgia's sake. Unfortunately the AI is so laughably bad and extremely predictable, ensuring that any player with half a brain can win on any difficulty on any map. Any map with 2 or more islands is especially problematic for the AI, as it doesn't seem to ever build transports, making it impossible to lose if you keep your eyes out for any hovercrafts.
The multiplayer component (Massive Assault Network, different game!) is a lot of fun, but Massive Assault itself can be skipped.

Okay, let's keep this short: the sequel, Phantom Renaissance, is a much better game, and it's got my actual review explaining why the series is basically the best turn-based strategy/tactics games I've ever played. Compared to this game, it has all the same mechanics, better graphics, and more units. The only reason to buy this one is for the singleplayer missions, and it's got a LOT of them. So either:

1. You already have Phantom Renaissance, in which case all I have to say is that this one has as many missions, and they're just as good. The AI is a little worse, and falls for cheap tactics much more frequently, but it's really not a bother.

2: You don't have any Massive Assault game, and you're wondering if the Massive Assault Collection is worth it. In which case... that actually depends on if you have a friend(s) who likes turn-based strategy/tactic games and might want the Collection too. Yup. You see, neither this game nor its sequel have multiplayer capabilities, while Network is nothing but. So if you just want to play singleplayer, you're better off getting Phantom Renaissance now and then deciding whether to get the 'extra mission DLC' once you've beaten it, because it'll only cost you €2. If you're also interested in multiplayer... while there's quite a lot of players still playing Network 2 (their site says 185 right now), you're really gonna want a friend if you want to play regularly. And if you do, you're better off getting the Collection even if you don't want this game in particular.

...Right, was that clear enough? Basically, don't even consider this game's existence until you've played Phantom Renaissance.

In any case, I still love the hell out of extra missions, so this is definitely a recommendation for me!

Like a turn-based cross between chess and C&C.

If you are looking for a Turn-based like Combat Mission, Battle Isle 4 TAW, or any tactical TB game, move along.
The Massive Assault series are more like Rock-Paper-Scissors + Chess games, the figures are tanks, the chess boards are islands. There´s no such thing like cover, accuracy or moral. Every unit hits enemies within range with 100% acc, and does full dmg according to the weapon.
Veterans of the Battle Isle 1-3 and similar games should give it a try, it´s hard, frustrating, but fun sometimes, everyone else, move along.
Edit: Stuck on missions where you can´t buy reinforcements, while the enemy can, MANY, and overruns you in a few rounds.

Extremly nice game. Has a little replay value too. Graphics not too great, but it still is good :)