I mean, I said it before, but I just re-read this and I'll say it again.
They really blew a big opportunity here.
This game seems like a whole lot of fun and strategy - even more so than regular chess. The entire angle of being able to put down bombs is crazy, and could lead to a whole lot of interesting game decisions. There could be all sorts of stuff about cornering each other, bluffing, etc. We got a taste of it, but not much of the real meat. The battle (after the rules were explained) took 20 pages in total. MC instantly made a mistake, goes for a bluff that gets called, and then does something nonsensical for the sake of it. We timeskip to the end where Guren quickly tricks the cheat, and checkmates her in one move.
The obvious comparison is No Game No Life. But let's actually look over its chess game in the beginning of that story, which also plays out into multiple phases. First, Shiro starts playing and almost immediately there's a twist - like here. Just like in this story, the enemy gets some advantage early on - however in this case, it's because Kurami can move her pieces in special ways. Now, rather than doing something nonsensical to take back the momentum, Shiro simply moves on after thinking about it. It's not portrayed as her laughing in the face of a hopeless situation - it seems like she can win despite the disadvantage. Again, we skip some time (although far less than this story does) and the enemy corners our Protag with another gimmick - except this time, it's that pieces don't want to commit suicide rather than mind reading. Now, let's compare: how do our protagonists win with their back against a wall?
In this story, it is revealed that everything was according to Guren's keikaku all along. He was always in a winning position, he just only now revealing his winning hand. In my opinion this is sloppy because we don't get a chance to realize this. It's not like we can watch the boardstate and see that he was getting her into position all along because they skipped most of the battle. We just have to take it as fact that Guren was never really in a losing position, and Tokitou just never realized it. It's basically an asspull.
In No Game No Life, Sora instead gives a rousing speech to motivate his soldiers and devolves the structured game of chess into an RTS warfare. He wins by seducing the queen and somehow turning the dumpster fire that used to be a chess game into a three-way battle. Yes, there's some asspull-ery here (why did that work in the first place?). But overall, we get a sense that the protagonists can be backed into a corner, and are just straight good enough to finagle their way out of it. In my opinion, this is a far superior resolution to "oh yeah I turned this around in a way that had absolutely no setup or foreshadowing".