Here at PC Gamer's office in the city of Bath in the UK, there is only one constant: it is always raining. So when my soldiers in this fantasy realm ask me to build a bit of overhead cover to keep their bowstrings dry and their spirits up while they defend my castle walls, I feel a lot of sympathy for their plight. But what they don't know is, I am a terrible architect. 

I knew this already, of course, because I discovered it last time I went hands on with promising upcoming RTS Cataclismo. Blending elements of strategy and tower defence with a wonderfully robust and clever building system, the game charges you with holding out against monster attacks by crafting your own walls and defences. 

The wide range of individual components let you put structures together piece by piece, like playing with a huge mediaeval Lego set. Clever players have the freedom to go wild with creativity and style, erecting castles that aren't just aesthetically pleasing, but functional too, taking advantage of all the nuances of Cataclismo's combat system. Me? I sort of bodge stuff together and hope it works. And then it doesn't. But this time, having a go at one of the game's Skirmishes—one-off maps that test your survival skills outside of the story-driven campaign mode—I'm determined to make a better showing for myself. My walls will be stronger, my economy more robust, and god damn it I'll keep my men dry if it kills me.

The perpetual rain is a feature of this specific map, and its effect is significant—soldiers without a roof over their heads suffer a hefty accuracy penalty, which isn't what you want when you've got an endless horde bearing down on you. Figuring out how to incorporate shelter into your defences while also juggling the many other nuances of the game's fortifications is a lovely little building puzzle, and it gets me wondering what other fun wrinkles I'll have to work around in the final game. 

But there's no time for day-dreaming about that—I've got monsters due to strike from the south, threatening to bulldoze through my vital stone quarry, so I get to work shoring up my defences. A stone wall is simple enough, and building mine across a hill allows it to have positions at different heights—that's important, because walls need to be tall to be at their strongest, but some soldiers operate best at lower heights than others. 

Along the walls I run a set of range-boosting merlons interspersed with damage-buffing banners, and set up a load of wooden scaffolding so my soldiers can easily get up to their posts. Now all I need is the roof over their heads—surely that'll be pretty simple?

Well, perhaps for someone else, but for me this triggers a whole new building crisis. There's a whole selection of roof pieces I can use, but they need supports, and the game is respectful enough of the laws of physics to prevent you from just building roofs across a whole wall extending off one big pole. That means I need multiple columns to keep the roof up, all taking up space on my already neatly ordered wall. At moments like this, Cataclismo becomes a game of both efficiency and sacrifice: finding the best, cheapest way to achieve what you're trying to do, but also determining what elements you're willing to lose to free up the space and resources to accommodate others. A lot of problems can be brute-forced by just throwing a load of extra wood and stone at them, but then what do you have left for your next wall when the monsters decide to come from another direction? 

Thanks to the generous recycle function, that lets me safely delete a load of my ill-advised initial placements, I'm able to cobble together the world's worst roof. It looks frankly bizarre, and it literally only just covers the thin strip of wall the soldiers will be fighting from, but damn it when I click on a unit and see they've cleared the “Rain-Drenched” debuff, I still feel a swell of pride.

That pride only grows when I confidently repel the first wave of creatures—my archers firing arrows from above, my lobbers chucking bombs from lower down to clear out the densest clumps, and my wizard finishing off the stragglers with magic missiles, all of them with perfect accuracy thanks to their bone-dry scalps. What a sight! 

When I see that the second wave is due to come from the same direction, I even allow myself a moment of smug confidence. With my economy now in full swing, churning out building materials and soldiers, I'm flush with ways to secure my wall even more tightly. I recruit a gang of trappers, a new soldier type that can slow enemies to make them more vulnerable to my other troops; I make space for new emplacements, such as one that grants any archers adjacent flaming arrows; and I lay out wooden spikes across key chokepoints to chip away at the horde as it advances. This wall could not be more impregnable.

Which is great, except for the part where I didn't notice there would also be a second horde attacking simultaneously from the east. RIP the people of Robin Town, who all die to this dastardly flanking manoeuvre, terrified but wonderfully dry. 

Oh well—like last time I got to play a chunk of Cataclismo, my defeat leaves me not despondent, but full of new castle-crafting ideas. A loss this complete is just an opportunity to skip back to the previous day using the generous auto-saves (explained in-universe as time magic, brilliantly) and try a different approach. The rain never stops, and neither does the building. 

Cataclismo is due out July 16, and you can check out a chunk of the campaign mode for a great taste of the experience with the free demo on Steam.