I'm having fun with ChessLocke.
Many years ago, I used to play a lot of a hilarious card game for chess named
Storm Over The Chessboard (Americans of course edited it in an entirely humorless, pseudo badass version named Knightmare Chess - know your audience
). The idea is that you play chess normally, but also play cards that allow special movies, from the most technical ones (swap your knight and your bishop) to the most unfair one (take an opponent's pawn if they've made an impolite remark), and all sort of wacky ones (have the opponent look away, grab one of their pieces on the board, and keep it if they failed to tell which one is missing), even going full crossver with other games of the same publisher (use that other game's dart pistol to try and shoot one of the opponent's pieces). Yes, fun times. Games used to get noisy pretty fast. Anyway.
Chesslocke is more sober and more serious. You earn XP during your game, you use them to level up your pieces and give them extra powers, such as shielding nearby pieces, promoting a pawn, swapping places, move an opponent piece, etc. The campaign is made of chess games with various start configurations (sometimes with walled tiles), and the AI plays quite seriously. Unlike Storm, the goal in ChessLocke isn't to checkmate the king (which can be catured like any other piece), but to spend one turn on the king's starting tile, dubbed the throne. This alone makes it an interesting take on chess.
I like chess variants with more or less crazy elements. Like the progressive army building of Majestic Chess, the shootouts of Warhammer 40k Regicide, even the kinda failed experiment (in my eyes) of 5D Chess. ChessLocke is one of the most fun so far.
Gotta try Shotgun King one of these days...