Hydra Slayer for Android
Hydra Slayer v13.0A by Zeno Rogue <firstname.lastname@example.org>, released under GNU General Public License version 2
This is the version of Hydra Slayer for Android devices.
Hydra Slayer is a
(that is, a game
where you control a single hero fighting horde of monsters,
with a high emphasis on tactics) where combat has been inspired by
some mathematical puzzles about brave heroes slaying many headed beasts.
Note that this might look like a standard dungeon crawler, but the
puzzle element is important, and the later game is meant to be challenging.
Try the tutorial first!
If you find any bug, or find that the tutorial does not explain everything
it should, please send me a report instead of just
uninstalling! I'll consider it for the next version.
- In most menus, you can touch a menu item (on screen) to activate it.
Most actions can be also selected by pressing the Menu button.
- On the race selection screen, click on the top part of the screen
(which contains race names) or use D-pad to change race, and then touch
the middle of the screen to play the chosen race.
- On the game screen, touch the corner which contains the list
of your weapons to switch weapons (the most common action), and touching
the corner which
contains the stats and list of enemies opens a single menu including all
possible actions (while Menu button shows just five). You can also touch
the message box at the bottom to see messages which did not fit on the screen.
Touching anywhere else is a move.
- Most common actions can be also executed by pressing hardware buttons.
For example, in the game, D-Pad moves, Volume Up and Volume Down switch weapons,
Call ("pick up phone") picks up items and climbs down stairs (just like
the 'g' key on keyboard), and Search opens your inventory (like 'i').
- In questions, touching the top of the screen means yes and the
bottom of the screen means no.
Hydra slaying has a long history.
First explorers who have met hydras were completely unable to do any harm.
As they cut hydras' heads, two new heads always grew in place of each one cut.
Some of them started using clubs instead of swords. However, this was only
a temporary solution. A club may stun a hydra, and make it temporarily less
dangerous, but not kill it. When time comes, it will wake up and attack
further. Hydras remained indestructible monsters.
Some mages have been employed to research methods of slaying Hydras.
The first thing they have invented were Runes of Decapitation, which could
kill a completely stunned hydra, or permanently destroy some heads of a
non-completely stunned one. Another thing were Runes of Cancellation, which
could remove hydra's regenerative abilities. However, both of these Runes
were one-use items and very expensive to create, and thus not practical.
Then, a report came, claiming that heads won't regrow if the sword was put
on fire. Apparently all Hydras in some region were killed using that method.
Their meat was found extremely tasty, their blood good for healing wounds
(due to hydras' natural regenerative abilities), and their scales good for
Mages tried this method. Unfortunately, it did not work for them, though.
However, they have experimented with other kinds of magically imbued weapons.
It turned out that some enchantments will reduce the number of heads
regrown. Possibly even no heads will regrow. Some hydras could be slayed
after these findings, but not all. It is rumored that some mage long ago
created a weapon which could slay any Hydra without regrowing heads, but
he got overconfident and killed, and the secret was lost.
Mages experimented with their magical weapons even further. And they had
a new result: weapons which could cut (or stun) several heads at once. If
they cut all heads, the hydra was killed. If not, the Hydra would usually
regrow the same number of heads as if only one head was cut. The mages were
happy with that major result.
Of course, some new hydra slaying weapons and magics were created later,
but they were nothing compared to the previous major achievement. The
numbers of Hydras kept decreasing, and finally, they disappeared, and
were almost forgotten... And less and less people became acquainted with
the hydra slaying techniques, as other people laughed at them, because
their profession was completely useless in these times.
Now you, a young student, have heard about a manifestation of hydras in so
called Hydras Nest. Apparently some brave knights came to kill the Hydras...
Brave, but stupid. Even if they equipped themselves with mighty hydra slaying
weapons, they had no knowledge about how to use them correctly. What use is
a mighty sword which can cut ten heads in one swipe, against a Hydra which
has only 9 heads? All these knights have been killed.
You are more clever. Since your earliest
years you have had an unnatural ability to count people in an instant, and
your great grandfather has suggested you to pursue the Hydra Slayer career,
and learn the forgotten art of Hydra Slaying. Now, you will show people that
it is not just an useless funny thing. You take two small magical weapons and
some magical items, hoping to rob better ones off dead bodies of these stupid
knights, and head to Hydras Nest. Of course, not that you are one of these
clever guys who are too scared and weak to be useful in a battle... you could
also wield a two handed weapon with one hand.
See the homepage for the PC version of Hydra Slayer
for more information and a beginner's guide.
Using the Keyboard
Since this is an Android port of a desktop game,
most commands can be also activated with keyboard. You can play solely
with touchscreen though, or mostly with hardware buttons and with touchscreen
occassionally (well, unless you want to rename your character).
In most cases the game displays the key that can be used to activate a command.
(Note: long pressing the Menu button displays the onscreen keyboard on some devices.)
Use arrow keys, numpad, or extended VI keys to move and to attack Hydras
with your weapons and active runes. Use numbers (1, 2...) or  keys to
switch your magical weapons of hydra slaying.
- q,S = go to the main menu
- i = view or use the inventory (runes, scrolls and potions)
- . = wait one turn
- f = present full information about hydras and items in sight
- d = drop currently selected weapon
- m = view recent messages
- g = pick up a weapon or item, or use stairs
- T = turn on/off auto-fire mode (press t to throw/shoot if on)
- v = description of the currently selected weapon
- c = switch twin control s = switch twin order
- o = auto-explore (see later)
- In most menus you can use arrows to navigate, Enter to select, and Space to cancel.
- When entering names you can press TAB to clear the current name.
In the main menu, you have an option to choose your geometry. Your options
are: (4) allow only horizontal and vertical movement, (6) simulate a hex
board, (8) allow movement in all directions. You change the selection by
pressing D, Space, 4, 6, or 8. Press '3' to create a game with variable
Your selection affects what directions are available to all actions,
including your movement,
hydra movement, missile weapons, grids targetted by Power Swipes, and so
on. Additionally, (6) makes levels smaller (because only each second
character is used) and (4) makes Hydras better at smelling you (for
If you are too bored to explore the Hydras Nest yourself, you can do
automatic exploration. It only works if there is no enemy in sight,
and will try to do the following, in order:
- pick up an inventory item you are standing on (unless a Troll),
- go to the nearest inventory item not behind mushrooms,
- go to the nearest non-explored space not behind mushrooms,
- go to the nearest inventory item through mushrooms,
- go to the nearest non-explored space through mushrooms,
- go to the stairway down.
Version 13.0a of Hydra Slayer has a Social version. This is a separate
application which includes
third-party social features, and it can be downloaded from the
However, the Social version is no longer supported in 14.0.
, which tell your friends
that you are playing Hydra Slayer, and what has happened. So, if you win a game, or simply find a nice
weapon or a particularly nasty Hydra, a message is generated, which you can easily post it to HeyZap.
provides global leaderboards and achievements.
You should be shown a login screen when you start the game, and then to access Swarm, simply press
Menu and "Swarm". Since Swarm does not allow long names for leaderboards, here is an explanation:
- first boss: wounds simply counts the number of HP lost until the first boss is dead.
The less, the better.
- first boss: treasure counts the total value of items (runes, scrolls, and potions) used
before defeating the first boss. The less, the better. This is called 'treasure' since you are
supposed to sell the remaining items (well, maybe not for a Troll).
- first boss: mutation counts how mutated you are. Whenever you defeat a Hydra, your
mutation score increases by the number of potions of Power Juice that you have used so far.
The value goes to the leaderboard when you defeat the first boss.
Thus, a smaller score means that you have won more cleanly, and thus is worth more.
- second boss works the same way, except that it counts the treasure and mutations when
defeating the second boss.
Savefiles and scorelists are written to /hydroid/ on your SD card.
The savefile format should be compatible with the PC version, so you can
start on one device and continue on another.
In case if Hydra Slayer fails to start, this is probably caused by
a corrupt savefile. Just delete /hydroid/hydra.sav on your SD card.
(This should not happen, but I write just in case.)
Hydra Slayer for Android (version 14.0) can be downloaded from the
It is released under GNU Public License version 2, and thus it comes with
absolutely no warranty.
You can also download the source (Hydra Slayer for Android 15.0)
or the APK: Hydroid.apk
If you like Hydra Slayer, please consider
You can contact me at email@example.com, or at
at my blog
(where I will publish future releases of Hydra Slayer).
- 12.1A Initial Android release.
- 12.2A Interface improvements.
- 12.3A Interface improvements for Android devices without hardware buttons.
- 12.4A Bug fixes. Algorithms have been improved.
- 12.4A1 Rebuild some menus. You no longer have both in-game help and website. In-game help now just redirects you to the website, which now contains all the information which was previously in Help. This should make everything clearer.
- 12.5A Due tu a forgotten edit all lower levels included Shadow
Hydras (and no other special enemies), fixed.
Auto-explore mode now works with a missile equipped.
Fixed bugs with Elves wielding divisors and standing next to mushrooms.
Shadow hydras now ignore arrows.
- 12.5A1 Fixed positioning of text (which caused the lowest line to be invisible).
- 12.6A Fixed problems which caused the game to freeze and close
after some time of playing. Also runs faster now. Fixed bugs with
auto-explore mode (did not want to go if an out-of-sight monster blocks the way,
sometimes got into an endless loop if trying with twins or after death).
- 12.7A The numbers shown when hit by hydras were incorrect, this is fixed. Many twin-related bugs fixed.
- 12.8A Fixed many bugs with the potions of knowledge. Fixed descriptions of some weapons. Stuntime now displayed for relevant weapons. A rare (?) crash bug fixed (hopefully).
You can now show the soft keyboard ("show keyboard" in the menu).
Should now detect corrupted savefiles, and offer to remove them.
Should no longer create empty savegames (which resulted in a slayer in an empty level).
Help updated a bit.
Other minor improvements.
Also try the new Swarm version ("Hydra Slayer Swarm") for social features like leaderboards and achievements!
- 13.0B social The social version adds HeyZap and has been renamed to "Hydra Slayer Social".
Added the "wounds" leaderboard. Fixed a bug with the "speed of light" achievement.
- 14.0 Major changes.