Impressive! :D
However I can understand that without a proper support request they didn't know that.

• A Tower Full of Cats – from $4.99 to $5.99 (+20%)

• Revenge of the Savage Planet - Cosmic Hoarder Edition – from $49.99 to $39.99 (-20%)
• Anger Foot – from $24.99 to $19.99 (-20%)
• Revenge of the Savage Planet – from $39.99 to $29.99 (-25%)

• Furi Demake - The Chain – from $0.0 to $2.99 (+inf%)

• DEFCON – from $9.99 to $11.99 (+20%)

• Blue Wednesday – from $19.99 to $14.99 (-25%)
• Blue Wednesday Deluxe Edition – from $29.67 to $21.57 (-27%)

Considering how sincerely surprised and delighted Introversion Software had been with the success of Prison Architect (to the point of later allowing Paradox Interactive to sink their add-on content-obsessed fangs into it), I am rather disappointed with the increase in price of this nearly 19-year-old game (even if I have derived nearly two decades of enjoyment from it). I do realize that a 20% increase is not all that significant, but, after such a long period of time has passed, I am curious as to why it had been deemed necessary.

Is it simply a matter of (slight) greed, or, as with a countless number of past lottery winners, has Introversion Software abjectly failed to properly manage their finances? Of course, the answer would be difficult to know with a sufficient level of certainty. Regardless of the underlying motivation, if this is the beginning of a trend (with their other games potentially following suit), it is troubling.

As feared, after writing the above, I had noticed the following:
Uplink: Hacker Elite - $5.99 --> $11.99 (+100%)

Darwinia - 10000th Anniversary Edition - $9.99 --> $11.99 (+20%)
Multiwinia - $9.99 --> $11.99 (+20%)
Scanner Sombre - $5.99 --> $11.99 (+100%)

As expected, this had occurred following the end of the temporary discount period.

• New Arc Line – from $19.99 to $24.99 (+25%)

• Baldur's Gate: Siege of Dragonspear – from $19.99 to $9.99 (-50%)

• Warhammer 40,000: Dawn of War - Anniversary Edition – from $34.99 to $14.99 (-57%)

• INAYAH - Life after Gods – from $24.99 to $15.99 (-36%)

• Die in the Dungeon – from $12.99 to $14.99 (+15%)

• Battle Realms + Winter of the Wolf – from $9.99 to $19.99 (+100%)

Someone else who has very weird ideas about what should happen to the pricing of old games...
Then again, maybe after being given away for free ten years ago but otherwise not being on sale in 7.5 years now it'll start getting promoted by 50% discounts whenever the wind blows.

Especially as Battle Realms is developed further on Steam, but the GOG version is left untouched since years and is severely outdated.

• Blood West: Dead Man’s Promise – from $14.99 to $9.99 (-33%)
• Reventure – from $7.99 to $4.99 (-38%)