Yes, I picked the computer option (the PC profile, keyboard and mouse), and the game does run fine for me. I didn't mean to say it was broken. The three points are smaller than that, and I just checked them against the build that's live now (19927137):
1. The radio line says "MOVE: WASD / ARROWS" (radio.js, the SOLO CHANNEL line). In ship mode game.js reads movement only from W/A/S/D and the left stick; the arrow keys are read as "a digital second stick for aiming/firing" (your own comment in that code). So arrows aim and shoot, they don't move the ship. That's a fine design, the radio text just says the opposite.
2. Capsules can only fall about 390 px before they expire, so ones dropped near the top of the screen never reach a ship that stays low. A player who plays it like a normal shmup can miss the main mechanic. A radio hint to fly up into the falling pieces would cover it.
3. Edge case: if you start holding the left mouse button during the 3-2-1 countdown and keep holding it, the ship doesn't fire until you let go and click again.
If one of these looks wrong on your side, tell me which and I'll run it again and send you exactly what I pressed.