The pixel art assets are cute. However, the game lacks enough possibility space to make for interesting play. Combat consists of spamming one attack button until you need to heal, which, okay, hey, that's just the usual RPG. The chess mechanics are shallow and vestigial at best, because their utilization extends hardly beyond the movement system, which itself is not backed up by interesting terrain or obstacle generation. Unlike previous comments, this isn't just a matter of "polish" — unfortunately I don't think there's enough of the substance to make for something standout. So, allow me to make a few suggestions:
* Complicate the combat system. Could still of course be something from RPGs, but this is too simplistic. The choice of keeping or discarding weapons is the only real meaningful choice to be made in the game, and this can be rather one-note. Consider expanding on this system as well.
* Make dedicated levels that utilize the chess movement mechanics in more interesting ways — or, if at all possible, cram unique and interesting level designs in 8x8 grid spaces. Having interesting and engaging level designs in a limited play space is one of the core tenets of good puzzle and strategy design, for example, so pulling inspiration from those genres could help you out here.
* Amplify the "roleplaying" of chess. Make stories. Write, and have fun with the war plotlines. Obviously, not feasible for a 4 day game jam, but if you ever consider expanding this game or doing something chess-related in the future, that'd be a great bet.
Even still, congrats on submitting for the jam. Be proud of what you were able to accomplish in such little time. I wish you all the best.
P.S. The countdown theme is also not very evident. Didn't even know I was timed on my moves before a 'boss' came, so more clarity on that would've been great.