Rules are simple!
Absolutely no doubt that if you like logic puzzles fit.

Rules
1. Connect dots with vertical / holizontal line and make one loop.
2. Numbers define how many lines can be drawn around it.
3. Lines cannot be crossed or branch off.

Slither Link
http://www.nikoli.co.jp/en/puzzles/slitherlink.html

The explanation about the button
[＋] Zoom In
[－] Zoom Out
[↓] A save of progress on the way(3 at the maximum)
[↑] The reading of the state of preservation
Long Tap: Undo the reading of the state of preservation

History
v1.26.13
– Bug fix
v1.26.12
– I made modifications so that a level was changed by a flick in puzzle list screen.
v1.26.11
– Bug fix.
ｖ1.26.10
– Bug fix.
ｖ1.26.9
– Bug fix.
– Faster drawing
– Undo the reading of the state of preservation
(Read button long press or Undo button)
v1.26.8
– Bug fix.
v1.26.7
– Bug fix.
v1.26.3
– Bug fix.
v1.26.2
– Bug fix.
v1.26.1
– Go back to the list screen after solved the puzzle
v1.26.0
– Corresponding to the URL that is output by the purepazu v3
http://pzv.jp/p.html?slither
v1.25.4
– Bug fix.
v1.25.3
– Responding to SlitherPuzzle2.
– Bug fix.
v1.25.1
– To speed up the initial startup.
– Added to the menu to initialize the play data.
– Bug fix.
v1.25.0
– Added 5 levels of Normal puzzle.
– Added 5 levels of Hard puzzle.
v1.24.0
– Added 10 levels of Normal puzzle.
v1.23.0
– Added 10 levels of Normal puzzle.
v1.22.0
– Added 5 levels of Hard puzzle.
– Added 5 levels of Very Hard puzzle.
v1.21.1
– Bug fix.
v1.21.0
– Added 10 levels of Very Hard puzzle.
v1.20.1
– Bug fix.
v1.20.0
– Added 10 levels of Normal puzzle.
v1.19.3
– Bug fix.
v1.19.2
– Add Undo/Redo
v1.19.1
– Bug fix.
v1.19.0
– Added 5 levels of Hard puzzle.
– Added 5 levels of Very Hard puzzle.
v1.18.0
– Added 10 levels of Very Hard puzzle.
v1.17.0
– Added 10 levels of Very Hard puzzle.
v1.16.1
– Fixed the update does not add a puzzle
v1.16.0
– Added 10 levels of Very Hard puzzle.
– Highlight where last touched
v1.15.0
– Added 5 levels of Normal puzzle.
– Added 5 levels of Hard puzzle.
v1.14.0
– Added 10 levels of Very Hard puzzle.
v1.13.1
– Operate together with the corresponding Slither Maker
v1.13.0
– Added 10 levels of Normal puzzle.
v1.12.0
– Added 10 levels of Very Hard puzzle.
– Add a level of solved
– Adjust the volume of sound effects with hard key
v1.11.3
– Bug fix.
v1.11.2
– When you load the progress, shown by dotted lines where the first touch
v1.11.1
– Bug fix.
v1.11.0
– Added 10 levels of Normal puzzle.
– Modified a check function to show a toast.
v1.10.2
– Bug fix.
v1.10.1
– Add a check function in the menu.
v1.10.0
– Added 10 levels of Normal puzzle.
v1.9.2
– Bug fix.
– Modified to verify when retry game.
v1.9.1
– Bug fix.
v1.9.0
– Added 5 levels of Hard puzzle.
– Added 5 levels of Very Hard puzzle.
v1.8.1
– Bug fix.
v1.8.0
– Added 10 levels of Very Hard puzzle.
v1.7.3
– Bug fix.
v1.7.2
– Helper “Color panel assist” separated by level.
v1.7.1
– Bug fix.
v1.7.0
– Bug fix.
– Added Full screen option.
– Added 5 levels of Hard puzzle.
– Added 5 levels of Very Hard puzzle.
v1.6.0
– Added 5 levels of Hard puzzle.
– Added 5 levels of Very Hard puzzle.
v.1.5.1
– Bug fix.
– Add Context menu.
v1.5.0
– Added 5 levels of Hard puzzle.
– Added 5 levels of Very Hard puzzle.
v1.4.2
– Bug fix.
v1.4.1
– Bug fix.
– Responding to Android 1.6(Cupcake).
v1.4.0
– Added 5 levels of Hard puzzle.
v1.3.2
– Correct mistakes of the data puzzle.
v1.3.1
– Correct mistakes of the data puzzle.
v1.3.0
– Fixed saving feature.
– Fixed scroll range of landscape.
– Added screen orientation settings.
v1.2.1
– Correct mistakes of the data puzzle.
v1.2.0
– Added 5 levels of Very Hard puzzle.
v1.1.1
– Bug fix.
v1.1.0
– Added 10 levels of Hard puzzle.