I enjoyed playing this one. It was tuned a little too difficult for me to get all the way through on stream after about an hour of playing, but that's not necessarily a bad thing.
The game page mentions that assets that weren't created by you would be listed in the credits, but I was not able to find those anywhere. If there are assets that were made available under creative commons or other licences, the jam rules do ask that those be noted on the game page.
This feels like a fairly polished entry, and as a whole, is a pretty solid realisation of the core concept, but I did come away feeling that either the shooting mechanic invites faster paced combat that the movement mechanics aren't quite up to or projectiles are a little too fast for the rest of the game. It also felt like there was a slight delay between input and firing that wasn't present for other inputs (jumping for example).
So far as Linux support goes, the Linux binary did not have executable permissions, and your game page did not contain instruction indicating that this is needed. You can direct players to enable this from the file properties dialogue of their favourite file browser, or if you're excited about managing that yourself, I made a free tool to make that easier from platforms that do not have/support executable permissions.
Always good to see a game with a beginning, middle, and an end. Unfortunately, I wasn't good enough at it to see the end, but I took a peek at the sources and spotted what looked like a final level. Nice work!