Visually this is one of the prettiest entries in the jam. Glowing neon vectors on black with bloom on everything: the mothership as a pulsing gold hexagon with a lit core, enemies as magenta and yellow triangles, and the orange MOTHERSHIP INTEGRITY bar underneath. It's lovely to look at and completely readable at the same time, which is a harder combination than it sounds.
And the legend panel on the side is one of the best tutorial solutions I've seen here. It lists all the enemy types by name (Chaser, Zigzag, Shooter, Tank, Splitter, Swarmer, Orbiter) and all five powerups, each with its icon colour. Then it gives you a reading key: red eye means it's hunting YOU, orange eye means it's attacking the BASE. That's real information, not decoration, and other entries in this jam should copy it. The combo system gives immediate feedback too, and keeping HIGH SCORE beside the current SCORE is the basic thing done right.
The biggest issue, and it's a design one rather than a bug: THE MODE BUTTON SITS INSIDE THE PLAY FIELD. It lives in the top right corner of the playable area, which is exactly where enemies come in from. I went to click an incoming triangle and accidentally switched from MOVE to SHOOT. In a game where you're clicking constantly, having a state button in the middle of the arena is a real problem.
Related: having separate modes for MOVE and SHOOT is already odd on PC. Your own footer says MOVE: MOUSE | SHOOT: CLICK, which suggests you don't need the mode at all on desktop. It makes sense on mobile, but on desktop it only adds confusion.
And one that will be costing you votes: the canvas doesn't follow the browser window. At 1280px I spent over 30 seconds thinking the game was empty, because enemies were spawning OUTSIDE the visible area. I only discovered there were any when I widened to 1600px. Anyone testing quickly through the jam list will conclude nothing spawns. That's worth fixing before anything else. Also, the legend panel, good as it is, sits over the play field and covers a big chunk of the bottom right corner.
Shipping it as a single self-contained HTML file with no obfuscation, download it and mod it, is a great end of life answer as well.