There are two new options on the game comparison page:
[ ] All Platforms
When this is checked, you aren't just comparing the game on the platform you selected, but also every other platform the game released on. This allows for much better comparisons of games that went from exclusive to multiplat or vice versa.
Examples:
The infamous Soul Calibur II vs Soul Calibur III comparison is now very easy to re-create by typing "Soul Calibur II" into the left box, clicking on the PS2 SKU, then typing "Soul Calibur III" into the right box and clicking on the result. The GameCube and Xbox versions of Soul Calibur II are automatically added to the sales totals and the graphs.
Cross-gen sequels to cross-gen games also work very well, here is Resident Evil Village and Resident Evil 4 Remake.
Right now this only looks at same-day multiplats.
[ ] Include Re-Releases
This option is helpful when you are comparing games where one or both had been re-released.
Examples:
Monster Hunter 2G and 3 with the option and without the option
Here's Super Bomberman R and Puyo Puyo Tetris 2 with and without their re-releases.
You can of course combine both options.
The COMG! comparison page will receive a similar update down the line as well.