Play Air Duel Online

I first came across Air Duel on MAME, the arcade emulator, a while back. It's a 1990 release from Irem, the same folks behind R-Type and a bunch of other solid arcade shooters from that era. It fits right in with that period's style of games: straightforward, tough, and built to eat quarters, but with a little twist that makes it stand out from the usual horizontal or vertical scrollers.

You pilot either a fighter jet or a helicopter, and your goal is to blast through waves of enemy aircraft and ground targets across several stages. The main gimmick is that you can flip your vehicle upside down at any time, which changes your firing angle and lets you hit enemies coming from above or below. You collect power-ups to upgrade your main shot and gain options, little drones that mirror your attacks. The pacing is relentless, with bullets and enemies filling the screen almost immediately, and the difficulty is pretty unforgiving, typical for Irem. It feels like a constant, frantic dance of flipping and firing just to stay alive a few seconds longer.