First off, Cheers are NOT Donations, they’re Tips. It’s an important distinction as it there’s a legal difference.
Secondly, you could either look at the bits tag in the cheer messages, as shown in the documentation https://dev.twitch.tv/docs/irc/tags#privmsg-tags
Alternatively rather than chat, a better option might be to use EventSubhttps://dev.twitch.tv/docs/eventsub as you can subscribe to types such as channel.cheer and receive notifications as and when cheers happen. EventSub over a Websocket transport is currently in beta so that could be ideal client-side in a game.