I don't want to say that the game is bad, but I will say the game is kinda bland. The main problem I have with this is the gameplay is confusing. Is it an FPS? Is it a Tower Defence game? It's trying to be some weird hybrid game, and because of that, it feels kinda frustrating to play, since you have three base points you need to defend, and sometimes the maps are so large, you have to stay in one place and hope your AI teammates are competent enough to protect the base. Not only that, but the batteries run out of charge way too quickly. What's that? You're curious about what batteries I'm talking about? Well, in this game, you have to arm your bases with batteries, otherwise your defenses you placed won't turn on. Why is this a problem? Well, remember how I said the maps are sometimes quite large? Yeah, on higher difficulties, you're gonna spend more time running around replacing your base batteries, swapping out batteries than being on the frontlines. To be fair, this is the most fun the game is, since it requires you to be maintaining your defenses and planning where you're going to be putting the majority of your defenses at, but batteries are oftentimes so scarce that you'll often need to defend the bases yourself with your gun, which is tedious. This wouldn't be as much of a problem if batteries wouldn't get knocked out by almost everything (do note on the hardest difficulty, Nightmare, all enemies are replaced with an explosive variant that instant kills you at close range and knocks out batteries if they're close to the terminals, and even on lower difficulties, these types of enemies get more and more frequent the later on in the game you get, and remember: No battery means no defense, meaning most of your time spent running around is just you making sure the battery isn't knocked out. Also get used to Max Ammo shouting in your ear that "THE POWER NODE IS RUNNING OUT" "DON'T FORGET TO KEEP YOUR TOWERS CHARGED"). Not only that, but there are some missions, where you don't have any place to put down defenses, and you are locked to using your gun, and these missions suck for one big reason: They're too simple. Just shoot the enemies. That's all it it. Shoot the enemies in a bland arena. One of these missions is literally impossible to fail since it doesn't even have a base to defend, it's just you in an arena fighting a super tanky boss.
But there has to be some good stuff to it, right? Well, yes, I wouldn't have wanted to 100% the game if there wasn't.
First off, this game is meant to be a retro style game, so there are tons of secrets you can find in the levels that unlock certain stuff, from secret character customization options, to new weapon skins, towers, and even cheat codes, these maps are super fun to explore in the free roam mode to find all the hidden collectibles, and can even help you with figuring out an optimal path for the harder difficulties. Not only that, but the overall setting is quite charming, as you play in a 90's style environment with designs that just ooze with personality. Last good note is that the multiplayer mode can be fun, as it focuses solely on the gunplay, making it feel like one of those classic multiplayer shooters, such as 007 and classic Halo.
However, as many good things I can think of with this game, I ultimately can't say it's something I want to come back to. The main campaign is just not fun, and the multiplayer, while fun, it's populated. I'd say only get it if you are REALLY curious, enjoy tower defense games / shooter games, or if you are just curious and it's on a decent sale.