Here's a quick rough concept of a handheld. It's a bit larger than a regular handheld, maybe 4" wide. It's meant to be usable and not a design turd for yuppies who want to fit everything in their pocket. The "SGRM", Shallow Games Restrictions Management, makes sure that only deep strategy games like X-COM, Dwarf Fortress, Total Annihilation, etc are playable on the device. If a Match-3 game is detected, the device explodes, sending broken glass shards into the face of the culprit.
+ Big screen, minimum 400×400.
+ Pressure sensitive touchscreen and pen with LMB/RMB
+ Analog joystick in the middle, reachable by both the left and right hand thumb.
+ Maybe some shoulder buttons on the back or on the side, I dunno.