In early 2009 (or, more likely, in late 2008), someone who goes by the name Pastel started working on a "thematically organized, largely nonlinear Metroidvania" game called Life+.
According to Pastel, the game is "more similar to Doki Doki Panic/Super Mario Bros. 2 than anything else, [as] the combat involves ripping up chunks of floor and hurling them at enemies and obstacles. You can pluck certain projectiles out of the air, stand on some particular enemies and rip them asunder, and stuff like that. When you pull up a tile, its constitution depends on what you're standing on and your luck. If what you're standing on is too thick, you won't be able to pull it up until you find a strength building powerup."
A year and a half later, Life+ remains a work in progress. Thankfully, interested gamers can keep tabs on that progress by visiting the Life+ Update Blog now and then.
In the meantime, check out this "video test," which shows off the game's Cave Story-esque graphics and Doki Doki Panic-ish gameplay:
Oh, and if you're at all interested in learning more about Life+, this blog post is a good place to start.