Minor troubles with installed programs in Linux Mint 15

Why is it that for some games in Linux Mint's Software Center/Manager, specifically older ones, they won't show up in my list of Applications? I've downloaded quite a few Linux games from the Software Center/Manager and perhaps only half of them show up/are executable.

Is there a way to fix this? I've tried uninstalling and re-installing them after chalking it up to being a glitch, but that did not seem to work or help.

have you tried going into teminal and typing in sudo app get?