Thanks — both of those were real, and both are fixed.
The 45 instead of 30 was the chain-length multiplier: a 3-tile chain is ×1.5, so 5 × 6 = 30 becomes 45. You could not see that anywhere, which is the actual bug. The damage popup now shows the whole breakdown, including any modifier that fired: "5 × 6 = 30 ×1.5 → +45".
The stage counter was simply wrong in the demo build: the demo stops after stage 2, but the HUD was reading the full game's 5. It now reads "Stage 1/2", so the stopping point matches the page.
Both are live in the browser demo — a hard refresh (Ctrl+F5) will pick them up. You played before that update went out.
Your note about stage two and modifier combinations is fair, and I am not treating one run as a balance verdict either. If you do go back in, the modifier shop after stage 1 is where the run actually gets decided.