Retro II

Retro II is a freeware vertically scrolling shoot-em-up released in 2006 by the Swedish independent developer cactus, and it is built around simple vector-shaped objects and a deliberately limited colour palette. The player fires with the Z key and taps X repeatedly to launch bombs, and picks up U-shaped weapon upgrades to raise the ship's firepower. It was covered on release by the Independent Gaming blog, which grouped it with the run of small freeware titles cactus put out that year.