Let me start off by saying bravo on making a phpbb forum look amazing not many people can so great job on that.
Theme & Customizations: I have to say that the theme you have chosen to use is a very professional and sleek looking theme that caught my eye as I've never seen it before on any forums so I applaud you for that. I like how it's not to flashy and cluttered I love how on the index the topics, posts and latest post are in boxes and very nicely done. The logo is a unique one and really goes with the theme and is very professional looking. I'm very pleased that you added a favicon so many people forget that and it makes the site look unprofessional and incomplete so very nice job on remembering that little detail.
The way you set up the forums is great as you made categories for the different topics and not just throwing them in random categories which some forums do. Your forum offers a wide range of topics to be discussed and will pull more users in as you cover a range of topics. I am a fan of the general category so members can have the ability to talk about other topics other than the main categories. I love the fact that you didn't go over board on the categories as some people do when making a forum.
All around it's a great start and it got me to join the forum. I wish you the best.