Illvelo Swamp + Radirgy Swag

Illvelo, also named Illmatic Envelope, is a vertical shoot-em-up initially released for the NAOMI arcade system by Milestone in 2008. It's mostly noticeable for its trippy level backgrounds, bizarre sound effects and wacky enemy visual designs, but the game system underneath is also very solid and worth diving into.

Radirgy Swag is a vertically scrolling shoot-em-up developed and published by RS34 for Nintendo Switch in 2019. It plays in horizontal orientation, with a slightly angled perspective (unlike many 2D shoot-em-ups that have a strictly top-down perspective).

The game's title and general aesthetics draw from the original Radirgy, though this game makes several departures from the traditional arcade format of its forebear. Radirgy Swag consists of a single continuous run with endless enemies (under certain circumstances) and no bosses or rigid stage transitions whatsoever. Also, this game features an energy meter that depletes over time and upon being hit by enemy attacks (but can be replenished with items), instead of the traditional lives system.