Brother, Allah granted you the gift of life for a preciously short amount of time on this earth. Not only that, each day that you wake up, remember that Allah returned your soul to your body to give you another day to repent, and use your day to make salah, donate zakah, make dawah, and struggle for the sake of Allah (fee sabeel ilah). You need to appreciate each precious moment that Allah has gifted you and use this time in Allah's cause. There is really no such thing as "free time". If Allah has given you "extra" time that is not needed (a gift most of humanity is not getting) for supporting yourself and your family, it is up to you spend this extra time in a manner most pleasing to Allah.
Your decision to spend this time to participate in video game entertainment, even if the games are sanitized of shameful, idolatrous, or degrading content, shows where your priorities for using your time are. On Yawmi Deen (day of judgement) you will be questioned about this use of time. Instead of spending your time participating in fantasy video game entertainment, you can spend your time to warn those who have fallen into sheydan's trap against squandering their precious time in idle or makruh activities.
So, to answer your question: participating in video game entertainment, even with sanitized content, while maybe not really commiting shirk, is sinful in the sense of squandering your precious time in idle activities.