Tomorrow, Crytek and EA Partners will ship Crysis Warhead, a PC-only follow-up to last year's Crysis that falls somewhere in between an expansion pack and a traditional sequel.

In addition to further optimizing the game code (Crytek hopes to combat the belief that high-end PC gaming demands thousands of dollars), the Crysis team learned a number of lessons about design and pacing, taking player criticism of Crysis to heart.

Though recently-formed Crytek Budapest took the lead on the project, there has been overlap from the first game -- such as with Bernd Diemer, a designer on that title who now serves as producer for the franchise.

Diemer recently sat down with Gamasutra for an in-depth postmortem-like discussion about Crysis Warhead's development, during which he addressed the reasoning behind the game's unusual format, the tricky balance between player guidance and player freedom, the maddening intricacies of NPC AI, and the problems with the often-maligned drastic shift in gameplay towards the end of the original Crysis.

Here, in a discussion shaped by Gamasutra editor Chris Remo, we present Diemer's own words about the development process of Crysis Warhead.

On Warhead's pseudo-sequel format: What we tried to do is the best of both worlds. Back in the day, when we first started thinking about Warhead, it started out as a vanilla expansion pack. That's the kneejerk reflex of developers: "We're doing a game? We're almost done? Let's do an expansion pack next."

The initial design was more along these lines. You needed the original game to play it, it was single-player only, and a lot shorter.

Then we brought in the Budapest team. Around that time, when we were finalizing Crysis, we were building up the Budapest team with their own project -- giving them full studio status within our small Crytek family. We brought them over to Frankfurt to meet everybody and get them trained on our tools and our engine. So we suddenly had twenty guys with weird names in our office, speaking a language nobody could understand -- although they speak English as well.

It was a very intense time for us, so we decided, "Let's have these guys take a look at the expansion pack we wanted to do." We told them, "Here's our box of toys. Please think about how we can improve it." Back then, we knew we should have done certain things in differently given more time or a less hectic development schedule.

They went and did prototypes in the editor, like what a mod team would do. They used whatever was available in Crysis to prototype new gameplay, such as the new vehicle rides, aliens breaking through the ice -- those made it from the first prototype video into the final game.

After we looked at all the ideas and prototypes they had for the then-expansion pack, we said, "No way is this going to be used in an expansion. We have to make it standalone." We then decided to develop a longer campaign -- a full single-player campaign -- but we kept the $29.99 price point, which leans more towards the expansion pack.

On structural comparisons to Valve's Half-Life 2 episodes: The main difference is that Valve continues the story. What we did is tell a parallel story on the other side of the island. It gave us the opportunity to evaluate our own franchise a bit more. Crysis Warhead is the first time we, as Crytek, explored a franchise we had ourselves created, past the original game. It was an opportunity to look at what we could do to keep it fresh.

We decided to have the first game's character of Sykes be the main hero, and tailor the game a bit more towards his personality and his love of blowing things up -- wherever he is, things tend to blow up around him. It's not always his fault, but very often it is. That drove the whole design.

We wanted to keep the original Crysis vision, which is the sandbox freedom and tactical freedom that allows you to play the game however you want -- stealth, action, whatever. From the beginning, there had to be a lot of things that blow up on the main path -- if you stick to the main path, it's a lot more action-driven than Crysis used to be.