Well, Giallone Remix is one of those with the least gain applied, on the other hand Panic Mouse and Creative Nature vol. 1 are more than twice as loud, but you’re right on average the entire CD is only two thirds up in gain.
1. NOISE MAKER THEME [+2.12 dB ~ 128 %]
2. THE MIND'S JOURNEY [+4.07 dB ~ 160 %]
3. PANIC MOUSE [+7.49 dB ~ 237 %]
4. GIALLONE REMIX [+3.87 dB ~ 156 %]
5. MERAVILLIA [+7.09 dB ~ 226 %]
6. CREATIVE NATURE VOL.1 [+3.04 dB ~ 142 %]
7. PANIC MOUSE (Stress Mix) [+8.16 dB ~ 256 %]
8. CREATIVE NATURE VOL. 1 (Adam & Eve) [+6.81 dB ~ 219 %]
9. THE MIND'S JOURNEY (Brain Mix) [+4.03 dB ~ 159 %]
– AVERAGE VOLUME INCREASE – [+4.45 dB ~ 167 %]
You can notice it especially in the lower volume parts of the songs, there is less noise and crackles (though not completely removed), but generally the hi-hat sounds suffer from that also in loud parts. Also for example in Giallone Remix, they removed the low frequency noise in the bell intro (0:00 to 0:22) but didn’t do the same in another similar sounding part (1:33 to 1:38).