First a big thanks to everyone I met at the Retro gaming fair Retrospelsmässan here in Sweden! I had a blast and it was great to meet you guys and talk about Prometheus!
Like I wrote in the previous blog post, I discovered a new bug in Prometheus in that the centaur boss disappeared mysteriously if you attacked it too soon after it appeared on screen. I thought I had fixed it, but it appeared again when playing the new version 1.1. However, I have traced down the problem to a compability issue between Windows 8 and Game Maker: Studio and games made in said program. After extensive attempts I can't recreate the bug on any of my Windows 7 machines, and staring at the code gives no result, so it has to be the operating system that is the culprit in this particular case.
I recommend playing Prometheus on Windows 7 if at all possible, Game Maker: Studio is not optimized for Windows 8 so there's not much I can do about it. It's not a big deal though, when you face the centaur simply wait with attacking until it has moved over to the other side for the first time. Alternatively you can "cheat" and make it disappear and just waltz on to the item, but it's not a good long-term strategy since you need to beat every boss in order to finish the game.
Edit: Apparently GM: Studio IS supposed to be compatible with Windows 8 according to Yo-Yo Games, but I find this dubious since the bug only appears on that OS.