O2Jam is an old 2005 vertical scrolling rhythm game (those games in which notes fall from the top to the bottom and you have to press the correspondent keys).
I tried a lot of Wine builds. Every build lags during the main gameplay of the game (it's not unplayable, but the lag is noticeable). The ONLY ONE version in which the game runs fine without lagging is the 2.10-staging version. However, the game has a mode called "hidden" (it puts a black area on the playfield to make the gameplay harder) and whenever you activate the mode the game drops a lot of frames. Funny thing is that the hidden mode problem doesn't happen in newer builds of wine, but as I was saying before newer builds suffer from lag during normal gameplay.
I'm not an expert about this stuff but maybe directdraw is involved. For example, Windows 10 players have to use a custom ddraw.ddl (https://fdossena.com/?p=wined3d/index.frag) to make the game playable. I tried to use it as an override on Wine with no luck.
If anyone has an idea on what is going I'd be more than happy!
