I had Fourth Encounter cartridge (Thorn Emi) and it was impossible open.. I got it open finally.. But covers dont look so nice anymore.. Board did go inside cartridge when I tryed it on Vic20 that was reason for opening. GAme works, but it hurts fingers remove it from Vic.
Another cart is Demon Attack... I have no idea how open it.. Game wont start it just goes to basic screen.. I have tryed cleaning and installing it to Vic20 again and again.. No help..
Isn't the casing different depending on manufacturer? Those I own have a screw on the bottom side, and then you carefully break it open, but I know that a "virgin" cartridge casing will not open easily. If you get yourself an expansion unit to load cartridges vertically, it may be easier to remove them too.
On cartridges with screw, the screw helps hold circuit board in place within cartridge. The screw may be under a label.
Some of the cartridges also have 2 tabs that need to be depressed to pull top & bottom halves apart, even after screw is removed.
I replaced screw with small bolt & nut to hold circuit board, and left top off for easy access and replacement of Eprom. Grabbing hold on bottom of cartidge case is much nicer on fingers than getting stuck with pins on bottom side of circuit board.
