added new entries

games/action/_toc.md

@@ -12,10 +12,13 @@
 - **[Biniax](biniax.md)** (C, zlib, mature, inactive since 2012)
 - **[Blobby Volley 2](blobby_volley2.md)** (C++, GPL-2.0, mature, inactive since 2017)
 - **[Blobwars: Metal Blob Solid](blobwars_metal_solid_blob.md)** (C++, GPL-2.0, mature, inactive since 2015)
+- **[Bombermaaan](bombermaaan.md)** (C++, GPL-3.0, mature, inactive since 2010)
 - **[Boulder Dash](boulder_dash.md)** (Java, MIT, mature, inactive since 2015)
 - **[C-Dogs](cdogs.md)** (C, GPL-2.0, mature)
 - **[Cabbages and Kings](cabbages_and_kings.md)** (Python, MIT, mature)
 - **[Cat Mother Dead Justice](catmother.md)** (C++, 3-clause BSD, beta, inactive since 2003)
+- **[Celestron](celestron.md)** (Python, GPL-3.0, beta, inactive since 2012)
+- **[Chocolate Doom](chocolate_doom.md)** (C, GPL-2.0, mature)
 - **[Chromium B.S.U.](chromium_bsu.md)** (C++, Artistic License, mature)
 - **[CommandoJS](commando_js.md)** (JavaScript, CoffeeScript, MIT, beta, inactive since 2012)
 - **[Epiar](epiar.md)** (C, C++, Lua, GPL-2.0, beta)

games/action/bombermaaan.md

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+# Bombermaaan
+
+_Classic bomberman game._
+
+- Home: http://bombermaaan.sourceforge.net/, https://sourceforge.net/projects/bombermaaan/
+- State: mature, inactive since 2010 
+- Download: http://bombermaaan.sourceforge.net/download.php, https://sourceforge.net/projects/bombermaaan/files/
+- Platform: Windows, Linux
+- Keywords: arcade
+- Code repository: https://svn.code.sf.net/p/bombermaaan/code/ (svn)
+- Code language: C++
+- Code license: GPL-3.0
+
+## Building
+

games/action/celestron.md

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+# Celestron
+
+_Top-down space shooter in the legacy of Chromium BSU._
+
+- Home: https://sourceforge.net/projects/celestron/
+- State: beta, inactive since 2012 
+- Download: https://sourceforge.net/projects/celestron/files/
+- Keywords: top down, shooter
+- Code repository: https://git.code.sf.net/p/celestron/code
+- Code language: Python
+- Code license: GPL-3.0
+- Code dependencies: Pygame, Numpy
+
+## Building
+

games/action/chocolate_doom.md

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+# Chocolate Doom
+
+_Doom source port that accurately reproduces the experience of Doom as it was played in the 1990s._
+
+- Home: https://www.chocolate-doom.org/wiki/index.php/Chocolate_Doom, https://sourceforge.net/projects/chocolate-doom/
+- State: mature 
+- Download: https://www.chocolate-doom.org/wiki/index.php/Downloads, https://sourceforge.net/projects/chocolate-doom/files/
+- Platform: Windows, Linux, macOS
+- Keywords: remake, shooter
+- Code repository: https://github.com/chocolate-doom/chocolate-doom.git
+- Code language: C
+- Code license: GPL-2.0
+
+Supports a number of games and mods based on the Doom engine.
+
+License of assets?
+
+## Building
+
+- Build system: CMake