Don't know about some of the other titles, but Sega absolutely ruined Sonic CD classic. 1.0 shipped as a svelt ~20 MB game developed by the folks behind Sonic Mania. It was great[1]. At some point, Sega decided it needed to go free to play, so they added ads and tons of bloat to the game[2]. It now sits at ~200 MB with in app purchases to disable the ads (which don't seem to work for some people). A real shame.

[1] https://www.cnet.com/tech/mobile/retro-rings-sonic-cd-hits-i...

[2] https://powerupgaming.co.uk/2016/10/27/sonic-cd-goes-free-to...

Edit: Looks like the "end of life" version (4.0?) disables the ads but keeps the bloat which is better than I hoped for.