Hydra Slayer has been updated to version 17.1. This means that features which were previously available only in the paid version on Steam are now free. These features include: random challenges, traps, a new type of equipment (orbs), animations of flying heads, music, and lots of bugfixes and interface improvements. See here for details about version 17.0, and for the further updates. Of course, you still need the Steam version for typical Steam features such as online achievements, leaderboards and trading cards, and new features planned for the future will get in the paid version first!
NotEye now uses LuaJIT instead of the standard Lua. This greatly improves the performance.
Better support for Unicode
NotEye is now better at handling Unicode, that is, characters outside of the standard ASCII. Thus, when using a font containing all Unicode characters, for example, Hydra Slayer can now display the appropriate symbol √ for Eradicator, and Brogue can use the Aries symbol ♈ to display grass (previously this was possible only with fonts supplied with Brogue). Probably there are still some cases where this does not work as well as it could -- see NotEye's GitHub repository for further developments.
Better support for Linux terminals
One of strengths of NotEye (compared to Libtcod) was always that a NotEye game could work in a system terminal -- this makes it easier to communicate with software such as ssh for remote playing or screenreaders for blind people, and is the preferred way of playing text roguelikes for some people. NotEye 8.4 improves this somewhat. Modern Linux terminals do support 256 color palettes, or even TrueColor -- the newest version of NotEye can use this, thus, if you are playing Brogue on such a modern terminal, it should look just like the graphical version, with Unicode symbols and truecolor lighting. Secondly, using this feature was somewhat complex -- in version 8.4 it is sufficient to set the environmental variable NOTEYEEXTRACONFIG to consoleout_curses() (for the traditional Curses output), consoleout_16(), consoleout_256(), or consoleout_truecolor() (these three options work only in Linux for now). Previously ADOM and Hydra Slayer had special scripts on Windows for enabling the console output -- using an environmental variable makes these scripts simpler.