The official listing is single-player
Tidy Up the Town is listed as a single-player game. The store features do not advertise cooperative sessions, multiplayer lobbies or a shared market. You should not buy it expecting friends to enter the same cleanup session based on a similarly named game’s description.
Leaderboards are a separate feature
Optional Steam and online leaderboards let players compare results. Comparing scores does not mean players can move objects together or share world progress. The official materials also describe no time limit or game-over state, so leaderboard participation is not required to enjoy the cleanup.
Check future announcements directly
If you are looking for a later co-op announcement, check the current store features and developer news before treating a rumor as a release plan. This article does not announce a multiplayer update. See the multiplayer-update explainer and game overview for the distinction between current features and future possibilities.