There are numerous examples of Tetris clones out there that have not been targeted by the IP holders.
https://www.debian.org/security/2002/dsa-205
And of course I only started poking around because it was a game I played very very often in the office at the time.
Looks like their current strategy is to collect a few heads (e.g., Xio) and post them on pikes outside the village gates pour décourager les autres. They may not be able to nail everybody, but you run substantial risk of being targeted.