The main difference is in scale (size of pieces, boards and obstacles) see the update: https://www.kickstarter.com/projects/1732812836/tank-chess/posts/2069558 . The Pocket game set contains everything as the Main game set, except the 20x20 board (which is available as an add-on).
It is not EU/US/etc. friendly because we don't plan to ship games from the EU, USA, etc. But we send our games to various countries in the world beside Kickstarter using postal services. We send packages stated as gifts and we don't indicate value. On that way, we bear the risk if the package gets lost (in such case we would resend it). So far, it hasn't happened, and nobody has paid for import taxes (customs).