AppSurfer is a nice website which allows to play Android apps on the Web. I have added
Hydra Slayer on AppSurfer
Works a bit slow, but if for some reason you want to try Hydra Slayer without downloading, or see how the Android version works, now you can :) You can play by clicking the screen (as you probably would on Android), or with the keyboard (see this page for the list of keys).
But don't forget that the real desktop version looks better, is more user friendly, and you can save game safely :)
HyperRogue is available too, but unfortunately it seems too slow yet.