Replays would be very nice to have... but are pretty far from straightforward to do. One day I'll take a real crack at it, but I suspect it'd take about a week of work just to figure out if it's going to work well or not.
Secondly, I like to work on writing small games as a hobby and really enjoy programming. I love to read Indie developer blogs like your own and appreciate your posts about the thought process behind some of your design decisions like the Modern Ship Designs blog post. Would you consider doing a blog post about the developer tools that you use? It looks like you are programming in Java, based on some of the information I have seen about modding. Did you write your own particle effect system? Did you start with some game framework to give you a head start, or have you had to start from scratch? All of the weapons and battle effects look awesome, I'd really like to know more about how this was accomplished.
Hmm. I appreciate your interest
I don't know that a post like that would be interesting to a lot of people, as it's bound to get rather technical and a bit dry. Still, might not be a bad idea, if there's something interesting to say.
But to answer your question, yeah, it's in Java, using LWJGL to get at the OpenGL and OpenAL calls. Aside from that, the engine is just about entirely custom. Well, we're using a library to decode oggs, so I guess that counts
Personally, I find that writing your own stuff vs using an existing engine ends up being about the same amount of effort. I'm sure there are exceptions - writing a full-featured 3d engine is going to take a *long* time (assuming one even has the chops to do it). Then again, if you know what you want, you don't actually need "full featured"...