Fortified!, a 1960’s sci-fi themed tower defense game made by Clapfoot, is at its essence a balancing act. A capable third-person shooter combined with the strategy of placing defensive structures, both between and during waves of Martian invaders, works quite well but it isn’t all good news.

Our team of heroes is led by the Captain, a stalwart American soldier with a classic Steve Rogers look. The Rocket Scientist is as quick as she is smart and favors explosives, while the Agent is possibly from a shady government organization and has access to weapons straight out of Area 51. Rounding out the quartet is the Spaceman, a space cowboy whose skills rely on freezing enemies.

The atmosphere is consistent, with the voice-over narration during animations and the classic sixties dramatic music tying well with the comic-book animation of the same era. There really are no sharp edges here – the Martians fall in line with the art style, as do the four different playable characters and any sort of sci-fi devices presented including rocket ships and ray guns.

Fortified! is built on the Unreal Engine 4, and with the number of explosions and tossed bodies it clearly makes good use of the physics engine. I should mention that just because an enemy goes flying does not mean it’s down for the count – and that sort of thing may be your undoing.

I don’t think there’s an element to the combat presented which the team at Clapfoot hasn’t thought about – I found no glitches, and other than one commentary I make later on, the game is solid. Enemies of varying types spawn and travel towards your base in a predetermined course. Airborne enemies will ignore barriers that ground enemies need to walk around, and as I mentioned your explosions could catapult injured enemies right to your base entirely by accident.

So it is with careful consideration that you need to buy, place, and configure your combat resources. There are ground structure weapons such as anti-air cannons, heavy mortars and anti-tank guns. Tesla coils, nitro freezers and the like mount to specific walls and blast sideways while single-use landmines of different varieties can be placed anywhere on the playing field.

Fortified! also introduces AI characters into the mix, where each person playing can have up to twelve troops at their command. The D-pad is used to instruct your followers to either defend their station, go to a particular location, rally at the base or move with you as a group. They will otherwise always engage the enemy, and while they can be beaten down, they eventually get back up.

The last resource is your character’s own weapon, of which you carry two. Each weapon, regardless of type, has two firing modes and a reload time that rivals that of loading a musket. Oddly enough, if you exhaust a weapon and switch after the reload cycle begins, it will continue reloading in the background. This gameplay choice encourages a frantic shooting mayhem that, when you don’t use it this way, is extremely frustrating as you wait precious seconds for the reload cycle to finish only to have two of your alternate fire shots deplete your ammo. It would seem that Clapfoot is encouraging weapon-switching, and having weapons automatically recharge when not selected would result in a better experience.

For each character there are up to five weapons to be unlocked, as well as twelve structures, including expendables and AI helpers. Furthermore, each weapon and structure has two alternate modes that can be accessed by spending an extra skill point. Unlock points are assigned by leveling up, but these points are not transferable between squad-mates, though you can respec (reset them) anytime and re-assign to different unlocked items.

Ultimately it means that to unlock each team member’s skills, you’ll need to grind away at levels easy enough to allow you to win, gaining only moderate experience at a time. Grind is the right word – with only two gameplay modes and a total of twelve maps for campaign and three for invasion, you’ll be playing the exact same scenarios over and over again.

The focus of the game is balancing, however, and per Clapfoot’s own description the game leans to play multiplayer. This could be a lot of fun, but due to our advanced playtime no multiplayer modes had any players to connect with. I imagine the endless wave mode could be far more entertaining with friends. Sadly there is no split-screen option, and given the game’s modest system resource demands I’m not sure why they omitted it as this could be a perfect couch co-op title.