While I mostly play horror games and leave the rhythm well alone, I was intrigued by this game. I've recorded a video for my YouTube channel though at time of writing this comment it's still rendering. However I found this game wonderfully unique and brilliant.
If you're interested in testing, I played the game for my channel on my Windows gaming rig which, with 32GB RAM, Intel i5-3470, GTX 970 and running off an SSD you can expect it ran flawlessy on its maximum graphics settings. I also have a iMac 7,1 (20" mid 2007 model) which I use to render my videos with. After reading other comments I tried the Mac version as well. I have upgraded the iMac's RAM to 4GB and its HDD to 2TB (still a mechanical HDD, not SSD) and for the most part it also ran smoothly, Averaging around 20fps at the iMac's standard 1,680 x 1,050 display during normal gameplay but when the visuals kicked in showing the horror part, and the girl flashing on screen, I noticed a marked drop in fps to around 10fps. So for those with an older machine of around 2007 or earlier I'd recommend the "Good" quality settings or lower for smooth gameplay.
I haven't tested it on an older desktop PC mind you as I don't have one, but I also tested this on my Acer Aspire E51 laptop which also only has an Intel Core 2 Duo, 4GB RAM and Intel HD graphics, but even at maximum quality it runs very smoothly all the way through. So I gotta say yes this is a very good game to play even on older machines.
If you want to see my playthrough (be aware I'm crap at rhythm games) it'll take the Mac around 10 hours to render with another 3 hours to upload, so I will be releasing it on Monday 4pm PST/7pm EST as part of my scheduled release time for videos.