Sinsoft previewed its game engine on April 21, 2009 and launched the 'insert coin' system.
The 'insert coin' system allows users to try Sinsoft's latest offering for 50 cents per play (or 2 coins) with a minimum purchase of $1(US). This micro-transaction type of payment system is suitable for indie video game companies because it allows the developer to release incremental versions of its latest game and have the clients try it out for as little as possible and give feedback, while the developer can still make money in return.
Sinsoft calls the combination of game engine and insert coin network technology the "Sinsoft Arcade Cabinet". Hence the use of Arcade Cabinet requires a constant connection to the Sinsoft arcade servers and therefore Sinsoft games are 'online' games and cannot be played offline.
All newly released version of the arcade cabinet are free to download. The client only pays on a pay per play basis.
The Briefcase is a mockup game to showcase Sinsoft's Game Engine named Radial. Sinsoft is currently working on a game to make use of the 'insert coin' technology. However The Briefcase does showcase the 'insert coin' technology by itself. So a client can download the arcade cabinet without buying any credit. They will simply be presented with an 'insert coin' prompt during gameplay. If they still want to play or try, they would have to exit the game, visit the Sinsoft online store and buy credit.
The Briefcase will always be a mockup game, so Sinsoft might use it for later demos etc. The idea is that its a generic demo where the objective is to get to the briefcase inside a complex filled with cool NPC characters.