Supergun is an arcade shooter built around escalation: enemies arrive faster and tougher, and weapon upgrades are what keep you ahead of the curve.
It's straightforward action — the interest is in whether your upgrades outpace the difficulty, which is a race you eventually lose.
An arcade wave shooter where enemies escalate and weapon upgrades are what let you keep up.
It's built around escalating difficulty, so the goal is how long you last and how high you score.
Yes — it runs in the browser with nothing to install.