as they play, though leveling up does not provide any in-game benefits. Chocolate Doom Chocolate Doom is a source port for Windows, Linux, macOS, AmigaOS 4, MorphOS, and other modern operating systems that is designed to behave as closely as possible to the original DOS executable ("Vanilla Doom"), going as far as to duplicate bugs found in the DOS executable, even bugs that make the game crash. This involves more than just leaving the bugs in the source code. Several bugs present in the DOS version (for example, the sky bug in Doom II) were fixed in the released Doom source code, so these bugs were recreated for Chocolate Doom. The first version of Chocolate Doom was released on September 7, 2005. As it is designed to be as close as possible to the DOS executable, it has no new features and lacks high resolution support. It supports OPL3 music emulation, as well as the standard MIDI output on its host operating system. It is a popular test engine for level designers, and among players who prefer unmodified Doom. By default, it simulates the behavior of doom.exe version 1.9 running under Windows 98, although it will simulate the executables from The Ultimate Doom or Final Doom if it detects their respective IWADs. Other ports Various versions of Doom exist for the Amiga computers, one well-known example of which is ADoom. Portable devices Nintendo DS A port of PrBoom was written for the Nintendo DS. PWADs and DEH patches are supported, but only by creating a separate file with arguments to load them on startup. Wi-Fi network play is supported when using a PrBoom server set up on a PC. Digita OS DOOMD was a port released for FlashPoint Technology's DigitaOS for digital cameras. The port is based directly on the 1997 source code release. Both Doom and Doom II IWADs are supported. Custom WADs are supported, but no selection interface has been implemented. iPod A hack allowed 5th generation iPods to run a port of Doom. It is also possible to run Doom on iPods running Rockbox's Rockdoom plugin. Zune and Zune HD Two ports have been released to run on Zune devices using OpenZDK. One for the Zune HD, and the other for third generation Zunes and lower. TI-Nspire Series A source port to the TI-Nspire graphing calculators (specifically the NDless jailbreak software) was created, titled nDoom. It is