Everplay Interactive have released a bit of a different type of 'endless' game onto Android. While this isn't an endless running or flying type of game, in Leaping Legends you'll be endlessly storming a castle in order to save a princess. This is done by climbing, jumping and dodging obstacles for as long as you can.
Leaping Legends comes with a variety of leaderboards to compete on as well as different missions/quests to complete. Finishing quests will earn you different rewards that contain different types of loot. There also happens to be plenty of achievements as well to try and earn.
As you get further into the game you'll be able to unlock different types of heroes, all of which will endlessly try to scale this castle at you command. While there is the usual Knight to play, you can also unlock other heroes like a ninja. You'll have to get really skilled though at this game if you plan to survive long enough to earn some of these things as Leaping Legends does get quite challenging the longer you live.
If you're up for a bit of a different type of endless game with a bit more of an entertaining theme, you might want to check this one out. You can download Leaping Legends off of Google Play for free.
Google Play Link: Leaping Legends
Forum Discussion: Leaping thread