Here's a game that will immediately appeal to some of my readers: a fangame dedicated to Lilith from Capcom's Darkstalkers/Vampire games! More exciting, though, is the developer: Mount Punch, who also developed the best game on the XBox Live Indie Games store, Chieri no Doki Doki Yukemuri Burari Tabi! Does it live up to that game's greatness? No. But it is still pretty good!
It's a platform game in which you play as Lilith, and you've got to traverse the various stages killing enemies and avoiding traps while also collecting enough bats to open the stage's exit. Later on, things get added like switches for opening doors and so on. The gimmick, though, is in how you get around the stages. Obviously, you can walk and jump, but the majority of your time playing the game will be spent flying in straight lines.
While in midair, you hold a direction and press jump to make Lilith fly in that direction, and while flying, you can also hold the melee attack button to turn her into a drill, smashing through enemies and certain kinds of blocks. To be honest, I don't know why you have to press a second button to do this, since there's no benefit to be found in flying without drilling, nor is there any disadvantage to doing it every time.
The game's clearly designed entirely around this mechanic, and it's in a certain category of game (my goto example always being the Playstation game Speed Power Gunbike) that offer little mercy to new players, but get significantly more enjoyable to players that persevere and master the idiosyncratic way the game plays. That is, when you first start playing, it'll seem unfair, clunky, and generally no fun at all to play. But once you master flying and drilling and you learn the stage layouts a little, there's a lot of fun and satisfaction to be had zooming from place to place, cleaning up bats, monsters, and destructible blocks as you go.
Lilithrottle is, like I said, definitely an acquired taste, but if you think you have the patience to properly get ahold of it (or if you're enough of a Darkstalkers fan for that to motivate you), you should definitely give it a try! If you just want to get through games while encountering very little friction, though, it's definitely not for you.