Here's a demo ROM of the game I'm working on: "Princess Lydie". (I promised a long time ago I'd make a 2nd game). It is somewhat inspired by Mario Bros (not Super).
Gameplay: Stomp or kick enemies, then kick them off-screen. Jump-up kick is very effective when timed correctly. Enemies stop for a short while after falling, some will recover quickly (especially the blue one). Snakes turn randomly afterwards, other enemies turn towards player.
Controls: left/right (up/down when holding control sideways). Any button to jump. When falling, press button to drop kick. Falling off-screen warps to the top - both player and enemies.
Notes: I can't test on real hardware. It is designed to be PAL-compatible, only "easy mode" is available (everything is a bit slower). In NTSC, that mode has some flickering on enemies.
Scoring is not implemented yet (no extra lives, which makes the game difficult). No in-game reset. Sometimes you'll just stand on an enemy: either jump, or, don't move.