are there any games like amplitude or wario ware for the pc (homebrew or otherwise)?
I can’t think of anything like those two games for PCs that’s available commercially.
Try Yohoho! Puzzle Pirates, It’s a MMORPG with puzzles instead of action. highly addictive, but you’ll need to pay monthly after 10 sessions.
But it’s not really anything like Wario Ware or Amplitude.
No and no.
Besides Frequency (and possibly Rez?) for the former, there aren’t any games like either of those two on any system.
No, Rez has the same trippy “Wow, it’s like a fun Winamp Plug-in” look to it, but the gameplay is in no way similar. The gameplay in Rez is your standard Sega on-rails shooter; hold down the button to lock onto enemies then release to fire, with the B button being a limited Kill-Everything-On-Screen maneuver. What sets it apart is that look and style that are tied to your progress through the level and help to draw you in, along with the soundtrack that builds as the level progresses as well. I don’t want to downplay how awesome Rez is, but it’s not a music game the way Amplitude and Frequency are. You could almost say they’re closer to a Dance Dance Revolution experience (for your fingers) than they are close to Rez.