1UP: You've stated that co-op play will be a big part of the sequel. How has it been working on co-op design and what are the challenges you've faced?

LH: Yeah, we're really excited about online co-op and we're keen to share the love. In Trine 2, everyone can experience the co-op fun -- or inadvertent mayhem as it may sometimes be, especially with three players. The co-op works on a drop-in/drop-out basis, and you can switch between single-player and co-op on the fly, so it's completely hassle-free, too. And of course, just to be perfectly clear, Trine 2 will have both online and offline co-op, so the couch is still a good option if you want to make sure your friends will face the consequences of their misbehavior.

The main challenge with co-op is in level design. Levels need to support co-op in addition to single-player and any number of characters on screen at once. And by support, I mean that the levels and the gameplay must be fun in both single-player and co-op. Luckily, I'm happy to say that our level designers have done a fantastic job so far and Trine 2 is going to be enjoyable for all players, no matter how many are playing. It's so fun that I'm spewing out marketing speak with ease, that's telling something!

What's great about the levels and the puzzles is that they support a great number of "solutions": there's no one way of doing things, getting past obstacles and so on. You always have multiple choices, even in single-player. Co-op adds another layer of possibilities and that's going to provide some nice replay value too.

We also wanted to make sure that every character has something fun to do at all times but the solution is actually the same: making sure that each puzzle and situation is possible to solve with any character. Of course some solutions are easier and some tougher, and the characters' different abilities play into this as well, but overall there's a lot more depth and even some complexity to the puzzles in Trine 2. We want to keep the player moving forward at a reasonable pace, though, and the almost limitless physics-based solutions certainly help at that. It will be very interesting to see what kind of cool solutions players invent in Trine 2 -- I bet we'll be surprised more than a few times by tricks that we hadn't even thought of!