Infinite Mario 64 takes the base platforming of Mario 64 (Something the game doesn't take advantage of), and allows you to generate levels based on Seeds. Stars are collected by collecting a specific amount of coins (if there are less than 100 on the level), 100 coins, and by getting to the end of the stage.
While bare bones in both obstacles and items to interact with, the formula already provides hours of enjoyment. Roaming around platforms and beating rather tough levels is great, and the level generation feature is pretty complex for what it is.

This game includes a "transparent background" feature, which supposedly allows you to use your own backgrounds, but it does not work for me and only turns the background black.

IM64 is infinite platforming fun, simple as. While it could use enemy placement, and other obstacles (lava, water, etc), what already exists is great fun.