If it's possible and the second game is completed maybe just make DLC for both games and on ci-en to see which game should get it and with DLC for games you can add new things like weapons features and functions maybe new characters that can tease the next game and other games you made.
Maybe even do a poll before the end of the game to see if the community wants DLC and let you get more time to make accounts and accommodate for dlsite and discord stuff so we can have a way to talk to community members and brainstorm ideas for the next game while we wait and have people with same interests and build up on ideas for the player and the community members.