Tried the game until level 3. It’s a really well done game and I liked the satisfying sound wheny you finish a extra combination :D I think it’s made with SDL, so even more effort from your side I appreciated. I just have few problems with the game. One is personal, because I like the fact you switch palettes and, even if the competition allows four colors per screen, that was a risky choice, because it improved the game, but I don’t think it’s really gameboy-ish. If the gameboy was able to do that, then it’s ok for me :) The other problem is technical, for some reason I can’t shutdown the game on Windows, I needed to terminate the process for closing it. So I liked your game really much, maybe add more variety to the game (so, not only combinations, but maybe some special blocks?).
Should have added some more messages about how to close the game in the main screen. There is a pause menu if you press Enter, from there you can save and exit the game! The color palette changes, I wanted to give the game a bit more of a Gameboy Color vibe than anything, even the music was heavily inspired by Tetris-DX on the GBC ;)
Special blocks are definitely in the cards if I'm going to continue working on the game! Maybe even make a "separate" version where each gem has its own color, with a more GBC aesthetic.