How hard has it been to work with the Source Engine mod tools to get the mod to work as you designed?

I can't say enough positive things about the Source Engine and the SDK. I loved the Source Engine as a gamer long before I worked with it as a designer and programmer. There are certainly little pitfalls and all that – no piece of software is perfect. But I think the mere fact that Dino D-Day exists as a playable game is a testament to the Source SDKs ease of use, flexibility, and low-barrier-to-entry for people unfamiliar with game design or modding (as I was).

Is there a detailed back story on how this world's Nazi got a hold of real dinosaurs?

We've worked up some back story but will flesh it out as characters settle into place and a more detailed sense of story begins to emerge. But to satisfy some of the curiosity out there let me just say that a German SS Officer, geneticist, and amateur paleontologist named Karl Krueger developed a method to extract a very special molecule from the fossilized bones of dinosaurs. Using this molecule, Krueger developed a method of creating embryos. Once they got embryos they got breeding pairs, once they got breeding pairs they got an army. Hitler was all too happy to unleash them on the Allies in 1942 – hoping to turn the tide of the war in his favor.
For people who haven't played the mod, tell us about the character that you play and the plot line for the mod?

In Dino D-Day, you will play as Sgt. Jack Hardgrave – a paleontologist in civilian life who volunteered for the Army. The mod centers on a Nazi transport train that Hardgrave sabotaged. This rather brief story is all you get in the mod – we focused more on the technical details of game design for the mod. The full game will open with the train wreck (with overhauled maps, cinematics, dialogue, etc.) and go on to take the player through an entire Dino D-Day storyline. We'll be revealing more detail on this as we go forward.

What dinosaurs do you have to combat in the mod and how hard was it to make them look and animate well with the Half-Life 2 mod tools?

The dinosaurs in the mod are: Triceratops, Velociraptor, and Tyrannosaurus Rex. One of the big challenges of this game is getting dinosaurs to agree with the Source Engine. There are some low-level difficulties that must be overcome to make them look and behave realistically. One thing everyone will notice when they play is that collisions with the dinosaurs heads and tails are somewhat infrequent. This is something we're working as the programmers who built the Source Engine built it more for NPCs that fit nicely into an upright rectangle. Dinosaurs heads and tails present problems for this. As far as animation and modeling goes...doing anything in a video game is pretty difficult. But once we got the hang of it we were able to get things done pretty quickly. Practice makes perfect!