It runs, but there is little you can do with it at present, as there isn't even any printer or PDF support.
Images can now be loaded, but they all seem to end up with a red hue, and text jumps about on the page when you load an image, but there is a primitive Word-Wrap function also built-in, but the default Bitstream Vera Sans TTF font need to be pre-loaded in SYS:Fonts/_ttf which is downloadable from the author's website along with a few other assorted TTF fonts, and there are other TTF Google Fonts available for download via GitHub -
GitHub - Hosting Google Fonts TTF - suitable for use with Cinnamon Writer the author states.
The author is aware of these shortcomings, and is currently working to fix them, so this does seem to be a W.I.P but there is a long way to go before we get something useful from it.
MacMini 1.5GHz,64MB VRAM, PowerBooks A1138/9 (Model 5,8/9),PowerMac G5 2.3GHz(DP), iMac A1145 2.1GHz 20", all with MorphOS v3.18+,Airport,Bluetooth,A1016 Keyboard,T-RB22 Mouse,DVD-RW-DL,MiniMax,Firewire/USB2 & MacOSX 10.4/5