The new Worms: Battle Islands game for PSP has base building and weapon creation tools. It's due this winter as a download from the PlayStation Store.
Battle Islands has Secret Island Bases that make up a new Tactics mode. Each player decks one out and they can be used either against the computer or online against friends. What bonuses are bestowed depend on the base you chose (there are 16) and the items you have. Some may grant you a free shot at an enemy worm before the match begins, while others may allow you a good look at the map's layout ahead of time.
Beat a friend and you'll be able to steal an item from their island. You'll also earn experience points to spend on unlocking more items.
Battle Islands will be the first 2D [I updated this Rob is an idiot -Ed] Worms game to allow weapons to be edited. Everything from missile weaponry to grenades to airstrikes can be tinkered with. That, coupled with the worm customisation tools, means no two squadrons should be the same.
On top of that, you can expect new environments to kill each other on as well as new weapons the Flare and the E.M.P.