The perfect video game still hasn't reached its final form, and Drop Duchy shows that "Tetris as a Civilization roguelike" is one heck of a twist

If there's any universal truth in the world of video gaming, it's this: Tetris is the perfect video game. With that in mind, the question about Drop Duchy isn't "Why would you combine Tetris with Civilization?" so much as it is "Why hasn't anyone else combined Tetris with Civilization before?" Drop Duchy can't match the impeccably brilliant design of its obvious inspirations, but these great tastes do nonetheless taste great together.

At the most basic level, a round of Drop Duchy takes place on a 7x11 grid, and you guide tetramino shapes from the top of the grid until they settle on a resting place at the bottom. The difference between this and Tetris is that the blocks are made up of various terrain types, like fields, forests, and mountains, and making a complete line rewards you with relevant resources, like food, wood, and stone. Complete multiple lines at once? That's a bonus to your resource stock.

Decked out

You also build your own deck of blocks that get shuffled into the queue with all the terrain, and most of the resources you gather will be spent upgrading these buildings. There are wood clearers that can turn forests into plains while giving you lumber, or farms that turn plains into farms for bonus food. You'll quickly see how these systems can stack with each other, letting you put together an engine that turns vast forests into food-producing machines.

These rounds are tied together with an overworld map that lets you choose between destinations with a vague preview of what's in store. If you're all in on farms, you might want to head to an area that's heavy on plains, or if you've got a loadout full of shepherds and stone quarries, it's probably better to get to the mountains to maximize your resource gathering.

But not all the lands you reach are peaceful. Some rounds will shuffle enemy garrisons, each of which has its own particular rules, into the block queue, and you'll need to place them yourself while putting down military structures of your own. Your watchtower gains archers from being placed among plains and fields, but so will enemy watchtowers, which means you have to be careful not to build that terrain such that you have to put the bad guys down where they'll get bonus units.

Each round culminates in a rock-paper-scissors-plus-math fight between every unit on the field. If I send my 25 archers against the enemy's 20 archers, I'll be left with 5 after the battle – those 5 are then going to be utterly destroyed by the 5 swordfighters the enemy still has left, unless I combine them with my axe battlers first. A smaller force will take on the unit type of any larger force it combines with, so 15 archers and 20 swordfighters will, together, become 35 swordfighters.

You can see how this kind of math starts to add up – pun intended – and this end-of-round skirmish is probably my least favorite part of the loop. There's no onscreen indication of how the numbers will come out as you draw up your battle plan, and the only way to see the results is by letting it all play out. All the math is simple enough that you can work it out with a notepad nearby, but I just don't want to put in the effort to figure out 'is 23 plus 59 times 1.5 enough to beat an enemy force of 125 and how many will be leftover' all that often.

Luckily, the math is made pretty much redundant with effective terrain and building placement during the round – 'big number beat small number' is simple enough for my English-degree-having brain to understand – and this is the heart of what makes Drop Duchy fun. Setting up an effective deck, placing terrain in preparation for lucky drops of your best buildings, and keeping the enemy barracks off in an ineffective corner is a satisfying challenge whose charm still hasn't dissipated for me, even after numerous runs.

Those runs are fairly short, as you can easily reach the final boss – which I still haven't managed to beat on the default difficulty – in under an hour. That's for the best, since the frequently expanding mechanical density of your deck can start to get to the edge of being too much to deal with. You get new additions to your loadout at a pretty fast rate, and if you're not constantly on top of switching out the most relevant options, you can quickly hit a disaster in the field.

Yet that level of challenge just makes the wins all the more satisfying. You can't improve on perfection, but Drop Duchy offers a meaningfully new take on the simple compulsion that defines Tetris. Dropping that line piece to finish off four rows of flawlessly placed terrain and buildings, reaping the resources and locking in my armies to utterly crush the enemy? Oh yeah, it's good to be king.

Drop Duchy is out now on PC. For more highlights, head on over to our Indie Spotlight series.