I think they made a huge mistake using this engine, but it's too late to change. I'm a new player to the series, never played the ARMA mod, just found the alpha through Steam. I love the direction the game is taking, but the engine itself is a massive problem. Combat as it stands feels absolutely horrible; melee combat is simply a swing-and-pray scenario, with very little ability to aim and poor hitboxes. Ranged is slightly better, but issues with desync make it an effort in futility at times as well. Physics at this moment are non-existent, AI is questionable at best, and then we get to performance issues, which this engine has in volumes. While I see that the team is making progress, it's been said many times that this is basically a new engine, and from my research, it seems that's the case. However, it's a "new" engine built on an old, out-dated engine. Had the team simply worked on their own engine from the ground up, I think the game might not be as far along, but would have more potential. Instead, I see the game being further along, but future additions will require significant amounts of recoding, if it can be done properly at all.